Washing machine

ABSTRACT

Disclosed herein is a washing machine including an inner tub assembly for accommodating laundry, a pulsator rotatably provided to an inner lower portion of the inner tub assembly, a blade installed at a lower portion of the pulsator to be rotatable independently from the pulsator, the blade being configured to pump wash water to raise the wash water to an upper end of the inner tub assembly, a drive motor for providing rotational power to the pulsator and the blade, and a power transmission unit for transmitting power of the drive motor to the pulsator and the blade, respectively. The power transmission unit includes a first planetary gear module for transmitting a rotational speed of the drive motor to the pulsator by decreasing the rotational speed, and a second planetary gear module for transmitting the rotational speed of the drive motor to the blade by decreasing the rotational speed.

TECHNICAL FIELD

The present invention relates to a washing machine for circulating washwater by pumping wash water to an upper portion of a washtub usingcentrifugal force.

BACKGROUND ART

Typically, a top loading washing machine refers to a washing machinethat allows laundry to be inserted and retrieved through the top of thewashing machine. The most typical type of top loading washing machine isa pulsator type washing machine. The pulsator type washing machinewashes laundry washed in a washtub containing a detergent, wash waterand the objects introduced thereinto, using wash water streams, andfriction and an emulsification process, which are caused by the washwater streams. The wash water streams are generated when wash water isforcibly moved by the mechanical force of a rotating pulsator, installedinside the lower portion of the washtub.

The pulsator, which is rotated by a drive motor, may create variouswater streams in the washtub through forward and reverse rotations.

Conventionally, a washing machine provided with a circulation pump forpumping circulation water at the outside of a washtub separately from adrive motor has been developed. This washing machine may cause even asmall amount of wash water to easily soak laundry (also referred to as“fabric”) which are introduced into the washtub, by pumping up washwater positioned at the lower portion of the washtub such that washwater is sprayed from the upper portion of the washtub onto the fabric.

However, if the pump is provided separately from the drive motor,additional costs are taken for purchase of the pump. Thereby, productioncosts of the washing machine increase, and control operation becomescomplex as the operation of the pump needs to be additionallycontrolled.

As shown in FIG. 24, Prior Art 1 discloses a washing plate 3 installedinside a washtub 1 to move up and down to pump wash water in a spacebetween the washtub 1 and an outer tub 2, an impeller 4 rotatablyinstalled in a lower portion of the washtub 1, and a power transmissionmeans 6 for decreasing and transmitting the rotational speed of a drivemotor 5 to an impeller 4. Wash water pumped by the washing plate 3 andthe impeller 4 is raised through a flow guide channel 3 and is thensupplied back to the washtub through a pumped water stream dischargehole 7.

As shown in FIG. 25, Prior Art 2 discloses a washing machine including apulsator 60 rotatably provided in a drum 30, a drive motor 50 mounted tothe exterior of the tub 20 to generate rotational power of the drum 30and the pulsator 60, a water stream creation means 70 provided to alower portion of the pulsator 60 to create a stream projected into thedrum 30 as a direct stream. The water stream creation means 70 includesa centrifugal blade portion 71 to create a spouting pressure usingcentrifugal force produced by rotation. The centrifugal blade portion 71and the pulsator 60 integrally rotate at the rotational speed of thedrive motor 50.

PRIOR ART LITERATURE Patent Document

Prior Art 1: Korean Patent Application Publication No. 2003-0049818(Jun. 25, 2003)

Prior Art 2: Korean Patent Application Publication No. 2013-004 9094(May 30, 2013).

Non-Patent Document DISCLOSURE OF INVENTION Technical Problem

In the case of conventional typical washing machines, dissolution of thedetergent and soaking of the fabric are implemented simply throughrotation of the pulsator with supplied wash water contained. Thereby,the solubility of the detergent is low and washing performance is thusdegraded. In addition, it takes a large amount of time to dissolve thedetergent and soak the fabric. Therefore, the present invention has beenmade in view of the above problems, and it is an object of the presentinvention to provide a washing machine capable of quickly implementingdetergent dissolution and fabric soaking by providing a structure forcreating water streams as well as a pulsator.

In conventional washing machines, wash water is supplied into an innertub up to a relatively high level to dissolve the detergent and soak thefabric. Thereby, the amount of water used for washing increases. It isanother object of the present invention to provide a washing machinethat facilitates dissolution of the detergent and fabric soaking evenwith a small amount of water.

In conventional washing machines, when the inner tub is rotating withthe laundry introduced into the inner tub and concentrated at oneposition, vibrations are generated in the inner tub. It is anotherobject of the present invention to provide a washing machine capable ofreducing exciting force generated by a pulsator to attenuate vibrationgenerated in an inner tub assembly when laundry are concentrated at oneposition in the inner tub assembly.

In the case of Prior Art 1, contact between the impeller 4 and laundryis limited, and thus washing force according to friction is mitigated.It is another object of the present invention to provide a structure incapable of pumping wash water upward while generating fresh air forceaccording to a contact between an impeller and the laundry.

In Prior Art 2, if the rate of rotation of the drive motor 50 isincreased to increase the spouting pressure through the centrifugalblade portion 71, the rate of rotation of the pulsator 60 mayexcessively increase, thereby interfering with smooth washing,increasing the degree of wear of the laundry, and even excessivelyincreasing load caused by the laundry. On the other hand, in Prior Art2, if the rate of rotation of the drive motor 50 is limited so as not toincrease the rate of rotation of the pulsator 60 beyond a predeterminedvalue, the spouting pressure according to the centrifugal blade portion71 is also limited. That is, in Prior Art 2, since the centrifugal bladeportion 71 and a pulsator 60 integrally rotate, both increasing anddecreasing the number of revolutions per minute of the drive motor 50may cause a problem. It is another object of the present invention toprovide a pulsator and a blade structure which rotate separately fromeach other.

In the case where a pulsator and a blade structure which rotateseparately using two drive motors are provided, additional costs ofcomponents of the drive motors are taken, and the whole shaft structurefor transmitting power from the drive motors needs to be changed.Further, motor control is additionally required. Therefore, it isanother object of the present invention to provide a structure fortransmitting power from one drive motor.

It is another object of the present invention to provide a washingmachine that provides both the function of increasing the pumpingpressure and the function of limiting the rate of rotation of thepulsator by increasing the number of revolutions per minute of a bladeand decreasing the number of revolutions per minute of a pulsator usingpower from the same drive motor.

It is another object of the present invention to provide a washingmachine which may enhance the functions of detergent dissolution, fabricsoaking and washing through complex water streams created by rotating ablade and a pulsator in different directions using power from the samedrive motor.

It is another object of the present invention to provide a powertransmission structure which may be designed by adjusting the number ofrevolutions per minute of a blade and the pulsator with a desiredreduction ratio using the power from the same drive motor.

It is another object of the present invention to provide a supportstructure for supporting a structure for transmitting power to a bladeand a pulsator using the power from the same drive motor, while notinterfering with flow of water streams. Solution to Problem

In accordance with an aspect of the present invention, the above andother objects can be accomplished by the provision of a washing machineincluding an inner tub assembly for accommodating laundry, a pulsatorrotatably provided to an inner lower portion of the inner tub assembly,a blade installed below the pulsator to be rotatable independently fromthe pulsator, the blade being configured to pump wash water to raise thewash water to an upper end of the inner tub assembly, a drive motorproviding rotational power to the pulsator and the blade, and a powertransmission unit transmitting power of the drive motor to the pulsatorand the blade, respectively.

The power transmission unit includes a first planetary gear moduletransmitting a rotational speed of the drive motor to the pulsator bydecreasing the rotational speed, and a second planetary gear moduletransmitting the rotational speed of the drive motor to the blade bydecreasing the rotational speed.

The first planetary gear module transmits power to the pulsator suchthat a rotational speed of the pulsator is decreased, and The secondplanetary gear module transmits power to the blade such that arotational speed of the blade is decreased.

Referring to seventh to tenth embodiments, which will be describedlater, the first planetary gear module may be disposed at an upper sideof the second planetary gear module.

Referring to the seventh to tenth embodiments, which will be describedlater, the washing machine may further include a washing shafttransmitting the rotational power of the drive motor. The firstplanetary gear module may include a first sun gear connected to thewashing shaft and integrally rotating with the washing shaft, a firstplanetary gear rotating by being engaged with an outer circumferentialsurface of the first sun gear, a first carrier connecting the firstplanetary gear using a first planetary gear connection shaft, the firstplanetary gear connection shaft being coupled with the first planetarygear by penetrating a center portion of the first planetary gear, and afirst ring gear having an inner side engaged with the first planetarygear, the first planetary gear being inscribed in the first ring gear.The second planetary gear module may include a second sun gear connectedto the washing shaft and integrally rotating with the washing shaft, asecond planetary gear rotating by being engaged with an outercircumferential surface of the second sun gear, a second carrierconnecting the second planetary gear using a second planetary gearconnection shaft, the second planetary gear connection shaft beingcoupled with the second planetary gear by penetrating a center portionof the second planetary gear, and a second ring gear having an innerside engaged with the second planetary gear, the second planetary gearbeing inscribed in the second ring gear.

The first planetary gear module transmits power to the pulsator suchthat a rotational speed of the pulsator is lower than a rotational speedof the drive motor, and the second planetary gear module transmits powerto the blade such that a rotational speed of the blade is lower than arotational speed of the drive motor.

Referring to the seventh to tenth embodiments, which will be describedlater, the pulsator may integrally rotate with one of the first carrierand the first ring gear. The other one of the first carrier and thefirst ring gear may be fixed to the inner tub assembly.

Referring to the seventh to tenth embodiments, which will be describedlater, the pulsator may integrally rotate with one of the first carrierand the first ring gear. The other one of the first carrier and thefirst ring gear may be fixed to one of the second carrier and the secondring gear.

Referring to the seventh to tenth embodiments, which will be describedlater, the blade may integrally rotate with one of the second carrierand the second ring gear. The other one of the second carrier and thesecond ring gear may be fixed to the inner tub assembly.

Referring to the seventh to tenth embodiments, which will be describedlater, the blade may integrally rotate with one of the second carrierand the second ring gear. The other one of the second carrier and thesecond ring gear may be fixed to one of the first carrier and the firstring gear.

Referring to the seventh to tenth embodiments, which will be describedlater, the pulsator may integrally rotate with one of the first carrierand the first ring gear. The blade may integrally rotate with one of thesecond carrier and the second ring gear. The other one of the firstcarrier and the first ring gear may be fixed to the other one of thesecond carrier and the second ring gear. The other one of the secondcarrier and the second ring gear may be fixed to the inner tub assembly.

Referring to the seventh to tenth embodiments, which will be describedlater, the power transmission unit may transmit power such that adirection of rotation of the pulsator is opposite to a direction ofrotation of the blade.

Referring to the seventh embodiment, which will be described later, thepulsator may integrally rotate with the first carrier. The blade mayintegrally rotate with the second ring gear. The first ring gear, thesecond carrier and the inner tub assembly may be fixed by each other.

Referring to the tenth embodiment, which will be described later, thepulsator may integrally rotate with the first ring gear. The blade mayintegrally rotate with the second carrier. The first carrier, the secondring gear and the inner tub assembly may be fixed by each other.

Referring to the seventh, eighth and tenth embodiments, which will bedescribed later, the first planetary gear module may include a firstgearbox housing accommodating the first sun gear, the first planetarygear, the first ring gear and the first carrier. The second planetarygear module may include a second gearbox housing accommodating thesecond sun gear, the second planetary gear, the second ring gear and thesecond carrier. The first gearbox housing and the second gearbox housingmay be rotatable relative to each other.

Referring to the seventh and ninth embodiments, which will be describedlater, the first planetary gear module may include a first gearboxhousing accommodating the first sun gear, the first planetary gear, thefirst ring gear and the first carrier. The first ring gear may be fixedto the first gearbox housing. The first carrier forms an upperconnection shaft penetrating an upper surface of the first gearboxhousing. The pulsator receives rotational power transmitted from thefirst carrier via the upper connection shaft.

Referring to the eighth and tenth embodiments, which will be describedlater, the first planetary gear module may include a first gearboxhousing accommodating the first sun gear, the first planetary gear, thefirst ring gear and the first carrier. The first ring gear may be fixedto the first gearbox housing. The first gearbox housing may form anupper connection shaft. The pulsator may receive rotational powertransmitted from the first gearbox housing via the upper connectionshaft.

Referring to the seventh and eighth embodiments, which will be describedlater, the second planetary gear module may include a second gearboxhousing accommodating the second sun gear, the second planetary gear,the second ring gear and the second carrier. The second ring gear may befixed to the second gearbox housing. The blade may be fixed to thesecond gearbox housing.

Referring to the seventh and eighth embodiments, which will be describedlater, the second carrier may be fixedly coupled with a lower surface ofthe inner tub assembly.

Referring to the ninth and tenth embodiments, which will be describedlater, the second planetary gear module may include a second gearboxhousing accommodating the second sun gear, the second planetary gear,the second ring gear and the second carrier. The second ring gear may befixed to the second gearbox housing. The blade may be fixed to thesecond carrier at a lower side of the second gearbox housing.

Referring to the ninth and tenth embodiments, which will be describedlater, the washing machine may further include a jig provided betweenthe pulsator and the blade and extending from an outer circumferentialportion of the power transmission unit in a radial direction of theinner tub assembly, the jig being fastened to an inner bottom surface ofthe inner tub assembly. The second gearbox housing may be fixed to thejig.

When viewed from an upper side of the pulsator, the blade may bedisposed to be fully hidden.

The washing machine may further include a wash water circulation modulefor guiding the wash water moved by the blade to an upper side of theinner tub assembly to spray the wash water.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a cross-sectional view of a washing machine according to anembodiment of the present invention, seen from a lateral side of thewashing machine;

FIG. 2A is a perspective view illustrating a pulsator and a circulationduct provided in an inner tub assembly of FIG. 1;

FIG. 2B is a cross-sectional view, taken along line A-A′ of FIG. 2A;

FIG. 3 is an exploded view of FIG. 2A;

FIG. 4 is a perspective view illustrating a jig 146 of FIG. 3 seated ona seating surface of a base;

FIG. 5 is an enlarged cross-sectional view illustrating a part of FIG.2B;

FIG. 6 is a cross-sectional view illustrating a power transmission unitof FIG. 2B;

FIG. 7 is a cross-sectional view illustrating fastening between thegearbox housing and jig of FIG. 5:

FIG. 8A is an exploded perspective view illustrating the pulsator andjig of FIG. 5 before being seated on the seating surface of a base;

FIG. 8B is a cut-away perspective view illustrating the pulsator and jigof FIG. 5, which are seated on the seating surface of a base;

FIG. 9A, is a perspective view illustrating a jig and a wash waterdischarge portion before being triple-fastened to the base of FIG.. 4;

FIG. 9B is a cross-sectional view illustrating the jig and wash waterdischarge portion triple-fastened to the base of FIG. 4;

FIG. 10 is a bottom perspective view illustrating an air gap formed inthe bottom surface of the jig of FIG. 4;

FIG. 11 is a cross-sectional view illustrating a power transmission unitaccording to a first embodiment of the present invention;

FIG. 12 is a cross-sectional view illustrating a power transmission unitaccording to a second embodiment of the present invention;

FIG. 13 is a conceptual cross-sectional view illustrating rotation of aplurality of gears engaged with each other, taken along line B1-B1′ofFIG. 11 and line B2-B2′ of FIG. 12;

FIG. 14 is a cross-sectional view illustrating a power transmission unitaccording to a third embodiment of the present invention;

FIG. 15 is a cross-sectional view illustrating a power transmission unitaccording to a fourth embodiment of the present invention;

FIG. 16 is a conceptual cross-sectional view illustrating rotation of aplurality of gears engaged with each other, taken along line B3-B3′ofFIG. 14 and line B4-B4′ of FIG. 15;

FIG. 17A is a cross-sectional view illustrating a power transmissionunit according to a fifth embodiment of the present invention;

FIG. 17B is a conceptual cross-sectional view illustrating rotation of aplurality of bevel gears of FIG. 17A engaged with each other;

FIG. 18A is a cross-sectional view illustrating a power transmissionunit according to a sixth embodiment of the present invention;

FIG. 18B is a conceptual cross-sectional view illustrating rotation of aplurality of bevel gears of FIG. 18A engaged with each other;

FIG. 19 is a conceptual cross-sectional view illustrating rotation of aplurality of bevel gears engaged with each other, taken along lineB5-B5′of FIG. 17B and line B6-B6′ of FIG. 18B;

FIG. 20A is a cross-sectional view illustrating a power transmissionunit according to a seventh embodiment of the present invention;

FIG. 20B is a perspective view illustrating the power transmission unitof FIG. 20A;

FIG. 20C is a cross-sectional view illustrating the power transmissionunit of FIG. 20A;

FIG. 21 is a cross-sectional view illustrating a power transmission unitaccording to an eighth embodiment of the present invention;

FIG. 22 is a cross-sectional view illustrating a power transmission unitaccording to a ninth embodiment of the present invention;

FIG. 23 is a cross-sectional view illustrating a power transmission unitaccording to a tenth embodiment of the present invention;

FIG. 24 is a view disclosed in Prior Art 1; and

FIG. 25 is a view disclosed in Prior Art 2.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to the preferred embodiments of awashing machine related to the present invention with reference to theaccompanying drawings. Wherever possible, the same reference numberswill be used even in different embodiments throughout the specificationto refer to the same or like parts, and redundant description thereofwill not be given. A singular expression includes a plural expressionunless the two expressions are contextually different from each other.

Throughout the application, the use of ordinal numbers such as “first,”“second,” “third” and so on serves to distinguish between respectiveelements rather than to denote particular ordering, importance orpriorities of those elements. For example, it is possible to implement adisplay apparatus including only a second element without a firstelement.

When one component is mentioned as being “fixed” to another, it shouldbe understood that the statement covers not only a case where a firstcomponent is directly combined with a second component, but also a casewhere the first component is combined with a third component, and thethird component is combined with the second component with the positionof the first component maintained relative to the second component.

As used herein, stating that a first component and a second component“integrally rotate” means that the first component and the secondcomponent rotate at the same rotational speed in the same direction.This covers not only the case where the first component and secondcomponent rotate by being coupled with each other, but also a case wherethe first component and the second component rotate together with thefirst component coupled with the third component and the third componentcoupled with the second component.

FIG. 1 is a cross-sectional view of a washing machine according to anembodiment of the present invention, seen from a lateral side of thewashing machine.

The washing machine shown in FIG. 1 includes a cabinet 100 defining theexterior of the washing machine, an outer tub 110 provided in thecabinet 100, and an inner tub assembly 120 rotatably installed in theouter tub 110.

The cabinet 100 may have a shape of a hollow rectangular parallelepiped.However, this shape of the cabinet 100 is merely an example, and theexterior shape and frame are not limited to the rectangularparallelepiped.

An upper portion of the cabinet 100 is provided with a door 101, whichallows an object to be washed to be introduced into and retrieved fromthe cabinet 100.

The outer tub 110 has a cylindrical shape with an open top. The outertub 110 is suspended from a suspension bar 111 in the cabinet 100. Theouter tub 110 stores wash water supplied from a wash water supply unit,and receives a detergent supplied from a detergent supply unit todissolve the detergent in the wash water and mix the detergent with washwater.

The inner tub assembly 120 is rotatably installed in the outer tub 110to accommodate an object to be washed and perform the washing operation.The inner tub assembly 120 is rotated by the power transmitted from adrive motor 130. The power from the drive motor 130 is selectivelytransmitted to the inner tub assembly 120 by control of a clutch. Theinner tub assembly 120 is held fixed during washing and rinsing, and isrotated during dehydration. The inner tub assembly 120 may include aninner tub 120 a provided with a plurality of dehydration holes, abalancer 125 mounted to an upper portion of the inner tub 120 a, a base121 coupled to a lower portion of the inner tub 120 a, and a hub 124coupled with the lower portion of the base 121. Wash water stored in theouter tub 110 is introduced into the lower portion of the inner tubassembly 120 through wash water introduction holes 124 a of a hub.

The hub 124 may be formed of a circular member thicker than the innertub assembly 120, and secure the overall rigidity of the inner tubassembly 120. The hub 124 is provided with a plurality of wash waterintroduction holes 124 a arranged in a circumferential direction.

The inner tub assembly 120 is rotatably installed in the outer tub 110to accommodate laundry therein and perform washing. The inner tubassembly 120 is rotated by power transmitted from the drive motor 130.The power from the drive motor 130 is selectively transmitted to theinner tub assembly 120 by control of a clutch. The inner tub assembly120 is held fixed in performing washing and rinsing, and is rotated inperforming dehydration. The inner tub assembly 120 may include an innertub 120 a provided with a plurality of dehydration holes, a balancer 125mounted to an upper portion of the inner tub 120 a, a base 121 coupledwith a lower portion of the inner tub 120 a, and a hub 124 coupled witha lower portion of the base 121. Wash water stored in the outer tub 110is introduced into the lower portion of the inner tub assembly 120through a wash water introduction hole 124 a of the hub.

A pulsator 122 is rotatably provided in the lower portion of the innertub assembly 120. The pulsator 122, which is a washboard, may include arotating plate 122 a, a center projection 122 b formed at the center ofthe rotating plate 122 a in a protruding manner, and a plurality ofprotrusions 122 c protruding upward from the upper surface of therotating plate 122 a. An upper cap may be installed at an upper portionof the center projection 122 b. The protrusions 122 c are spaced acertain distance from each other in a circumferential direction. One endof each of the protrusions 122 c is connected to the center projection122 b, and the other end of each of the protrusions 122 c extends towardthe outer circumference of the rotating plate 122 a. Herein, theprotrusions 122 c may be curved upward to rotate wash water introducedinto the inner tub assembly 120 in the forward/reverse directions tocreate water streams. The pulsator 122 receives power from the drivemotor 130. The pulsator 122 obtains an effect of rubbing and washinglaundry through water streams rotating in the forward/reversedirections.

The pulsator 122 is provided with a plurality of through holes 122 a 1,and wash water may flow down to a lower portion of the inner tubassembly 120 through the through holes 122 a 1.

A concave groove 122 b 1 is formed in the bottom surface of the centerportion of the pulsator 122, and a power transmission unit 140, 240,340, 440, 540, 640, 740, 840, 940, 1040 according to first to tenthembodiments, which will be described later, is provided therein. Thepower transmission unit 140, 240, 340, 440, 740, 840, 940, 1040 mayinclude a planetary gear module. The power transmission unit 540, 640may include a plurality of bevel gears. The power transmission unit 740,840, 940, 1040 may include a dual planetary gear module.

The power transmission unit 140, 440, 740, 840, 940, 1040 transmits therotational power of the drive motor 130 to the pulsator 122 bydecreasing the rotational speed of the drive motor 130. As therotational speed of the drive motor 130 is decreased and transmitted tothe pulsator 122, torque of the pulsator 122 increases.

The power transmission unit 240, 340, 740, 840, 940, 1040 transmits therotational power of the drive motor 130 to a blade 123 by decreasing therotational speed of the drive motor 130. As the rotational speed of thedrive motor 130 is decreased and transmitted to the blade 123, torque ofthe blade 123 increases.

The power transmission unit 340, 440, 540, 640, 740, 1040 transmits therotational power of the drive motor 130 to the pulsator 122 and theblade 123 such that the pulsator 122 and the blade 123 rotate in theopposite directions. The rotational speeds of the pulsator 122 and theblade 123 increase relative to each other, and more complex waterstreams are created.

The blade 123 is rotatably provided to a lower portion of the pulsator122. The blade 123 is installed below the pulsator 122.

The blade 123 serves to raise wash water to an upper portion of theinner tub using centrifugal force.

The blade 123 includes a circular rotating plate 123 a. The blade 123includes a plurality of pumping blade portions 123 b protruding downwardfrom the lower surface of the rotating plate 123 a. The rotating plate123 a serves to receive rotational power transmitted from the drivemotor 130, and the pumping blade portions 123 b serve to rotate washwater filling a portion below the rotating plate 123 a to pump washwater using centrifugal force. One end of a pumping blade portion 123 bis arranged spaced from one end of other pumping blade portions 123 baround the center portion of the rotating plate 123 a in thecircumferential direction, and the other end of each of the pumpingblade portions 123 b extends radially toward the outer circumference ofthe rotating plate 123 a.

The washing machine includes a wash water circulating module for guidingwash water caused to flow by the blade 123 to an upper side of the innertub assembly 120 and spraying the same. A plurality of wash watercirculating modules may be provided. In this embodiment, two wash watercirculating modules are provided. The two wash water circulating modulesare symmetrically disposed with respect to the center of the rotationshaft of the inner tub assembly 120 such that they face each other.

The wash water circulating module includes a wash water dischargeportion 127 coupled to the base 121. Wash water caused to flow by theblade 123 is introduced into the wash water discharge portion 127. Thewash water circulating module includes a circulation duct 126 providedto the inner surface of the inner tub 120 a to guide wash waterintroduced into the wash water discharge portion 127 to an upper end ofthe inner tub 120 a. The wash water circulating module includes a filterunit 128 disposed at the upper end of the inner tub 120 a to spray washwater guided through the circulation duct 126.

The circulation duct 126 is connected to the inner tub assembly 120 toprovide a circulation flow channel 126 a for raising wash water from thelower portion of the inner tub assembly 120 to the upper portion of theinner tub assembly 120 and resupplying and circulating the same into theinner tub assembly 120.

The circulation duct 126 may be mounted on the inner circumferentialsurface of the inner tub assembly 120 in the form of a cover. The backsurface of the circulation duct 126 is open, and the side ends of thecirculation duct 126 may be formed through curling or be curved. Theback surface of the curling portion is provided with a fastening lug,and the circulation duct 126 may be fastened to the innercircumferential surface of the inner tub assembly 120 by the fasteninglug. The inner circumferential surface of the inner tub assembly 120 maybe provided with a vertically elongated slit, and the fastening lug maybe inserted into the slit so as to be fastened. A space (flow channel)allowing wash water to rise therethrough is formed in the circulationduct 126. The circulation duct 126 defines a space, namely a circulationflow channel 126 a independent of the inner space of the inner tub 120a, such that wash water in the circulation flow channel is not mixedwith wash water in the inner tub 120 a.

The wash water discharge portion 127 is connected to a lower portion ofthe circulation duct 126. The wash water discharge portion 127 is apassage for receiving wash water discharged by the blade 123 and movingthe same to the circulation duct 126.

The wash water discharge portion 127 is disposed at an outer lowerportion of the base 121. The wash water discharge portion 127 includes awash water discharge port formed at a lower portion of a discharge body127 a and a duct communication port formed at an upper portion of thedischarge body 127 a.

The discharge body 127 a may be formed to be round. Thereby, when washwater moves from the blade 123 to the circulation duct 126, the movementdirection thereof may be smoothly switched from the radial direction tothe vertical direction.

The wash water discharge port may be communicatively connected to theinner portion of the base 121 and disposed to face the outercircumferential portion of the blade 123, and wash water pumped by theblade 123 may be introduced into the discharge body 127 a through thewash water discharge port.

The upper side of the discharge body 127 a is communicatively coupled tothe circulation duct 126 via the duct communication port, and wash waterintroduced into the discharge body 127 a rises into the circulation duct126.

The filter unit 128 may be installed at the upper end of the circulationduct 126.

The filter unit 128 includes a filter housing 128 a and a filter formedin a net structure provided in the filter housing 128 a. The holes ofthe net are very small. For example, the diameter of the holes of thenet is a few μm to a few hundred μm, small enough to filter out all finelint from the laundry. In the case of the pulsator 122-type washingmachine for washing laundry through the rubbing operation, a lot ofimpurities including lint may be separated from the laundry. In thiscase, when wash water containing lint passes through the filter,impurities including the lint may be removed from the wash water.

The lower side of the filter housing 128 a communicates with the upperend of the circulation duct 126, and one lateral face of the filterhousing 128 a communicates with the interior of the inner tub 120 a. Onelateral face of the filter housing 128 a is provided with an outlet 128a 1. The outlet 128 a 1 has a small vertical height and a largehorizontal width. Thereby, pumped wash water may be sprayed through theoutlet 128 a 1 onto a wide area in the inner tub.

The outer lower portion of the outer tub 110 is provided with the drivemotor 130.

The drive motor 130 provides power for driving the pulsator 122 and theblade 123 through rotational power from one motor. A washing shaft 132 atransmits rotational power of the drive motor 130. The drive motor 130is connected to the pulsator 122 and the blade 123 by the washing shaft132 a. Thereby, when the drive motor 130 operates, the pulsator 122 andblade 123 will be rotated. If the pulsator 122 or the blade 123 isconnected to the power transmission unit 140, 240, 340, 440, 740, 840,940, 1040, it may be rotated at revolutions per minute different fromthe rotational speed of the drive motor 130. If the pulsator 122 or theblade 123 is connected to the power transmission unit 340, 440, 540,640, 740, 840, 1040, it may be rotated in a direction opposite to thedirection of rotation of the drive motor 130.

The drive motor 130 may include a motor casing 131 and a rotor andstator, which are provided in the motor casing 131. The stator is fixedto the interior of the motor casing 131, and the rotor is rotated byelectromagnetic interaction with the stator. The rotor is connected tothe drive motor 130 to rotate the rotation shaft 132. The rotation shaft132 extends upwardly from the bottom surface of the center portion ofthe motor casing 131 toward the interior of the inner tub assembly 120.The washing shaft 132 a is provided to an upper portion of the rotationshaft 132 to transmit power to the pulsator 122 and the blade 123. Thedrive motor 130 is integrally connected to the washing shaft 132 a,which will be described later.

The power transmission unit 140, 240, 340, 440, 740, 840, 940, 1040 isdisposed between the drive motor 130 and the pulsator 122. Thereby,power of the rotation shaft 132 is transmitted to the pulsator 122 viathe power transmission unit 140, 240, 340, 440, 740, 840, 940, 1040. Inaddition, as the power transmission unit 140, 240, 340, 440, 740, 840,940, 1040 is disposed between the drive motor 130 and the blade 123, thepower of the drive motor 130 is transmitted to the blade 123.

The power transmission unit 140, 240, 340, 440, 740, 840, 940, 1040 ispositioned at an inner lower portion of the inner tub assembly 120. Morespecifically, as the power transmission unit 140, 240, 340, 440, 740,840, 940, 1040 is disposed between the pulsator 122 and the blade 123,the installation space for the power transmission unit 140, 240, 340,440, 740, 840, 940, 1040 may become compact, thereby reducing the volumeof the washing machine.

The bottom surface of the outer tub 110 is provided with a drainageport.

The drainage port discharges wash water stored in the outer tub 110after washing is completed. The drainage port is connected to a drainagehose. One end of the drainage hose is connected to the drainage port,and the other end of the drainage hose is connected to the outside ofthe cabinet 100. Thereby, the drainage hose discharges wash water usedfor washing and wash water obtained through dehydration after washing iscompleted.

Hereinafter, a description will be given with reference to FIG. 2A, 2Band 3.

The inner tub assembly 120 is provided with a base 121, which definesthe bottom surface of the inner tub. The upper portion of the base 121is coupled to the lower end of the inner tub through welding or curling.The lower portion of the base 121 is provided with step portions 121 band 121 c. The lower portion of the base 121 is provided with a firststep portion 121 b. The lower portion of the base 121 is provided with asecond step portion 121 c.

The blade 123 is disposed to be completely hidden when viewed from theupper side of the pulsator 122. When viewed from the upper side, thepulsator 122 is disposed to cover the entire inner tub assembly 120.Because the upper side of the blade 123 is hidden, the blade 123 cannotcome into contact with an object to be washed inside the inner tubassembly 120. Thereby, when rotating, the blade 123 is not subjected toload attributable to contact with the object to be washed, but issubjected to load resulting from pumping of wash water. The pulsator 122is provided so as to come into contact with the object to be washed.

The entirety of the base 121 is depressed downward. As the base 121 isdepressed downward, a space is formed between the bottom surface of thebase 121 and the lower surface of the pulsator 122. The blade 123 isdisposed in the space between the outer surface of the base 121 and thelower surface of the pulsator 122.

When the base 121 is viewed from the upper side, the center portion (theportion close to the center) of the inner tub assembly 120 forms thelowest upper side surface. A second step portion 121 c and a first stepportion 121 b are sequentially arranged in the direction from the centerportion to the edge. As a position is shifted from the center portion ofthe base 121 toward the edge thereof along the upper surface of the base121, the upper surface of the base 121 is raised by the second stepportion 121 c. As a position is shifted from the second step portion 121c of the base 121 toward the edge thereof along the upper surface of thebase 121, the upper surface of the base 121 is raised by the first stepportion 121 b. The first step portion 121 b extends circumferentiallyaround the rotation shaft 132. The second step portion 121 c extendscircumferentially around the rotation shaft 132.

The base 121 is also provided with a round portion 121 a roundeddownward. The round portion 121 a minimizes friction with laundry andallows wash water to easily flow down the inner tub assembly 120. Whenthe base 121 is viewed from the upper side, the round portion 121 a isdisposed at the edge of the base 121. The round portion 121 a extendscircumferentially around rotation shaft 132. When the inner tub assembly120 is viewed from the upper side, the round portion 121 a is inclineddownward from the edge of the base 121 to the rotation shaft 132. Theedge of the round portion 121 a is connected to the lower end of theinner tub 120 a.

The round portion 121 a is provided with projections 121 a 1, which areinclined upward facing each other. The projections 121 a 1 are arrangedspaced a certain distance from each other in a circumferentialdirection. As the projections 121 a 1 protrude from the round portion121 a upward, the strength of the base 121 may be enhanced, and therubbing effect produced by the stirring operation of the pulsator 122may be maximized in performing washing.

The first step portion 121 b is formed to surround the outercircumferential portion of the pulsator 122. When viewed from the upperside, the inner tub assembly 120 is disposed at the inside of theperiphery of the first step portion 121 b. The first step portion 121 bincludes a vertical surface vertically arranged to face the outercircumferential portion of the pulsator 122. The first step portion 121b is connected to a lower portion of the round portion 121 a. The upperportion of the first step portion 121 b is connected to the innercircumferential portion of the round portion 121 a (the end portion ofthe round portion 121 a proximal to the rotation shaft). A certain gapis formed between the first step portion 121 b and the outercircumferential portion of the pulsator 122. Thereby, interferencebetween the first step portion 121 b and the pulsator 122 may be avoidedwhen the pulsator 122 rotates. As long as the gap between the first stepportion 121 b and the pulsator 122 is large enough to avoidinterference, a smaller gap is the better. For example, a gap as smallas 1 mm is enough to prevent a coin coming out of an object to be washedfrom falling thereinto.

The second step portion 121 c is formed to surround the outercircumferential portion of the blade 123. When viewed from the upperside, the periphery of the second step portion 121 c is disposed at theinner side of the periphery of the first step portion 121 b. When viewedfrom the upper side, the periphery of the second step portion 121 c isdisposed at the inner side of the periphery of the pulsator 122. Thesecond step portion 121 c includes a vertical surface verticallyarranged to face the outer circumferential portion of the blade 123. Thesecond step portion 121 c is connected to the bottom surface of the base121. The center portion of the base 121 forms the lowest surface. Thelower portion of the second step portion 121 c is connected to the outercircumferential portion of the center portion of the base 121.

The bottom surface of the base 121 is provided with an opening. Theopening is formed at the center of the center portion of the base 121.Water may be introduced from the outer lower portion of the base 121into the base 121 through the opening of the base 121.

The bottom surface of the base 121 is provided with a hub 124. The hub124 is disposed at the center portion of the base 121. The hub 124 maybe formed of a circular member thicker than the inner tub 120 a, andsecure overall rigidity of the inner tub assembly 120. The hub 124 isprovided with a plurality of wash water introduction holes 124 a. Whilethe wash water introduction holes 124 a are illustrated as having an arcshape, embodiments of the present invention are not limited thereto.

A seating surface 121 d is horizontally formed between the first stepportion 121 b and the second step portion 121 c in a circumferentialdirection. A jig 146 for fixing the power transmission unit 140, 240,440, 640, 940, 1040, which will be described later, is seated on andfixed to the seating surface 121 d. The jig 146 is fastened to theseating surface 121 d. The need for the jig 146 depends on theembodiments.

The sun gear 142, 242, 342, 442, planetary gears 143, 243, 343, 443 andring gear 145, 245, 345, 445 of the power transmission unit 140, 240,340, 440, which is provided with a planetary gear module, aresequentially disposed from the rotation shaft 132. If a gear integrallyrotating with the blade 123 is disposed closer to the rotating plate 123a than a gear integrally rotating with the pulsator 122 among the sungear 142, 242, 342, 442, planetary gears 143, 243, 343, 443 and ringgear 145, 245, 345, 445, the jig 146 is needed. The jig 146 isimplemented in the first, second and fourth embodiments, which will bedescribed later. In this case, a gear arranged farther from the rotatingplate 123 a than a gear integrally rotating with the blade 123 among thesun gear 142, 242, 442, planetary gears 143, 243, 443 and ring gear 145,245, 445 is fixed. The position of the gear fixed by the jig 146 isfixed relative to the position of the inner tub assembly 120. The jig146 fixes the remaining gears other than the gear integrally rotatingwith the blade 123 or the pulsator 122 among the sun gear 142, 242, 442,planetary gears 143, 243, 443 and ring gear 145, 245, 445.

In the power transmission unit 540, 640 provided with a plurality ofbevel gears, the first bevel gear 5421, 6421 and third bevel gear 5423,6423 are sequentially disposed from the lower side to the upper side. Ofthe first bevel gear 5421, 6421 and third bevel gear 5423, 6423, if agear integrally rotating with the blade 123 is disposed lower than theother gear integrally rotating with the pulsator 122, the jig 146 isneeded. The jig 146 is implemented in the sixth embodiment, which willbe described later. In this case, the jig 146 fixes a second bevel gear6422. The position of the second bevel gear 6422 fixed by the jig 146 isfixed relative to the position of the inner tub assembly 120. The jig146 fixes the remaining gears other than the gear integrally rotatingwith the blade 123 or the pulsator 122 among the first bevel gear 6421,second bevel gear 6422 and third bevel gear 6423.

A first planetary gear module 740 a, 840 a, 940 a, 1040 a and secondplanetary gear module 740 b, 840 b, 940 b, 1040 b of the powertransmission unit 740, 840, 940, 1040, which is provided with a dualplanetary gear module, are sequentially disposed from the upper side tothe lower side. A first sun gear 742 a, 842 a, 942 a, 1042 a, firstplanetary gear 743 a, 843 a, 943 a, 1043 a and first ring gear 745 a,845 a, 945 a, 1045 a of the first planetary gear module 740 a, 840 a,940 a, 1040 a are disposed sequentially from an proximal position to adistal position with respect to the rotation shaft 132. A second sungear 742 b, 842 b, 942 b, 1042 b, second planetary gear 743 b, 843 b,943 b, 1043 b and second ring gear 745 b, 845 b, 945 b, 1045 b of thesecond planetary gear module 740 b, 840 b, 940 b, 1040 b are disposedsequentially from an proximal position to a distal position with respectto the rotation shaft 132. One of the first planetary gear 743 a, 843 a,943 a, 1043 a and the first ring gear 745 a, 845 a, 945 a, 1045 a isintegrally rotatably connected to one of the second planetary gear 743b, 843 b, 943 b, 1043 b and the second ring gear 745 b, 845 b, 945 b,1045 b. The other one of the first planetary gear 743 a, 843 a, 943 a,1043 a and the first ring gear 745 a, 845 a, 945 a, 1045 a is integrallyrotatably connected to the pulsator 122. One of the second planetarygear 743 b, 843 b, 943 b, 1043 b and the second ring gear 745 b, 845 b,945 b, 1045 b is integrally rotatably connected to the blade 123. Inthis case, four combinations are possible, which will be described inthe seventh to tenth embodiments. If the second planetary gear 943 b,1043 b among the second planetary gears 743 b, 843 b, 943 b, 1043 b andthe second ring gear 745 b, 845 b, 945 b, 1045 b integrally rotates withthe blade 123, the jig 146 for fixing the second ring gear 945 b, 1045 bis needed. The jig 146 is implemented in the ninth and tenthembodiments, which will be described later. In this case, the jig 146also fixes one of the first planetary gear 1043 a and the first ringgear 945 a, which are integrally rotatably connected to the second ringgear 945 b, 1045 b. The position of the gear fixed by the jig 146 isfixed relative to the position of the inner tub assembly 120. The jig146 fixes the remaining gears other than the gear integrally rotatingwith the blade 123 or the pulsator 122 among the first planetary gear743 a, 843 a, 943 a, 1043 a, the first ring gear 745 a, 845 a, 945 a,1045 a, the second planetary gear 743 b, 843 b, 943 b, 1043 b and thesecond ring gear 745 b, 845 b, 945 b, 1045 b.

The jig 146 is disposed between the pulsator 122 and the blade 123. Inanother embodiment, if the jig 146 protrudes longer than the diameter ofthe pulsator 122 in the radial direction, a cover for covering the jig146 may be needed. For the inner tub assembly 120 according to thisembodiment, the base 121 is formed to have two step portions, and thepulsator 122 and the jig 146 are surrounded by the first step portion121 b with the same diameter. Accordingly, the cover for covering thejig 146 is not needed.

To transmit power of the drive motor 130 to the power transmission unit140, 240, 340, 440, 740, 840, 940, 1040, a washing shaft 132 aintegrated with the upper portion of the rotation shaft 132 of the drivemotor 130 is provided. The power transmission unit 140, 240, 340, 440,740, 840, 940, 1040 includes a plurality of gears. The gears include asun gear, a planetary gear, a ring gear, a first bevel gear, a secondbevel gear and a third bevel gear.

The jig 146 fixes one of the gears. The jig 146 is fastened to the innerbottom surface of the inner tub assembly 120 to fix the position of thegear fixed to the jig 146 among the gears relative to the position ofthe inner tub assembly 120.

The washing shaft 132 a extends vertically upward from the bottomsurface of the base 121 so as to be inserted into the power transmissionunit 140, 240, 340, 440, 740, 840, 940, 1040, penetrating the centerportion of the hub 124 and the center portion of the blade 123.

The center portion of the blade 123 is provided with a circular shaftcoupling portion 123 c, and the washing shaft 132 a is coupled to theshaft coupling portion 123 c. Thereby, the rotational power of the drivemotor 130 is transmitted from the washing shaft 132 a to the blade 123via the shaft coupling portion 123 c. Accordingly, the blade 123 mayrotate at the same rotational speed (revolutions per minute) as thedrive motor 130, for example, at 300 rpm even higher than the rotationalspeed of the pulsator 122. The rotational speed of the blade 123 maysecure a desired pumping pressure and pumping head, increase the pumpingspeed of circulation water flowing along the circulation duct 126, andincrease the spray force for spraying water through the outlet 128 a 1of the filter housing 128 a. In addition, fabric may be sufficientlysoaked even with a small amount of water.

Hereinafter, a specific description will be given of the firstembodiment, with reference to FIGS. 1 to 10. Description of all elementsin FIGS. 1 to 10 are applicable to the second to tenth embodiments,which will be described later, except for the configuration of the powertransmission unit 140 and presence or absence of the jig 146.

The power transmission unit 140 includes a sun gear 142, a plurality ofplanetary gears 143, and a ring gear 145. The power transmission unit140 includes a carrier 144. The sun gear 142, the plurality of planetarygears 143, and the ring gear 145 are provided in a gearbox housing 141.The carrier 144 is provided in the gearbox housing 141.

The power transmission unit 140 receives power via the sun gear 142connected with the washing shaft 132 a. The power transmission unit 140transmits power by decreasing the rotational speed according to the gearratio between the sun gear 142 and the ring gear 145. The powertransmission unit 140 transmits power to the pulsator 122 via thecarrier 144, which connects the plurality of planetary gears 143.

The ring gear 145 is fixed to the inner tub assembly 120. To fix thering gear 145, the gearbox housing 141 is provided with a ring gearaccommodation groove 145 a, and thus a portion of the ring gear 145 isinserted into the ring gear accommodation groove 145 a. The gearboxhousing 141 not only restricts the vertical movement of the ring gear145, but also restricts rotation thereof. In addition, the gearboxhousing 141 may be fixed to the inner tub assembly 120 by the jig 146.

The jig 146 may support the outer lower portion of the gearbox housing141. The jig 146 is disposed between the pulsator 122 and blade 123. Thejig 146 may be fixed to a portion of the base 121.

The jig 146 may include a center coupling portion 146 a fastened to theouter edge portion of the gearbox housing 141 by a fastening member 146b 1 and an extension 146 b fastened by the seating surface 121 d of thebase 121 and a fastening member 127 b 3.

The center coupling portion 146 a has a ring shape, surrounds the lowerportion of the gearbox housing 141, and is fastened with the gearboxhousing 141 by the fastening member 146 b 1 such as a screw.

The extensions 146 b radially extend from the center coupling portiontoward the first step portion 121 b of the base 121. The extensions 146b may be disposed spaced from each other in the circumferentialdirection. Two adjacent extensions 146 b may be connected to each otherby a connector 146 c. The extensions 146 b are seated on the seatingsurface 121 d of the base 121 and fastened to the seating surface 121 dby the fastening member 146 b 1 such as a screw.

The wash water discharge portion 127 further includes a coupling member127 b circumferentially extending from the opposite lateral surfaces ofthe discharge body 127 a. The coupling member 127 b is disposed tooverlap the jig 146 and the base 121 in the thickness direction, and isfastened to the jig 146 and the base 121 by the fastening member 127 b3.

The coupling member 127 b may have the shape of a circular arc along thesecond step portion 121 c with a curvature identical or similar to thatof the second step portion 121 c. The coupling member 127 b includes anupper surface allowing the fastening member 127 b 3 to pass therethroughand a lateral surface vertically extending down from the upper surfaceand having a certain curvature.

The coupling member 127 b is provided with a fastening groove formedtherein and a nut portion 127 b 1 for fastening the fastening member 127b 3. A reinforcement rib 127 b 2 connecting the outer circumferentialsurface of the nut portion 127 b 1 to the lateral surface of thecoupling member 127 b may be provided, thereby reinforcing the couplingmembers 127 b. An end of the extensions 146 b of the jig 146, theseating surface 121 d of the base 121 and the nut portion 127 b 1 of thecoupling member 127 b are disposed in an overlapping manner in thethickness direction, and the three overlapping members are fastened toeach other by the fastening member 127 b 3.

Referring to FIGS. 2A to 4, a balancer 125 is mounted to the upper endof the inner tub. The balancer 125 has a circular ring shape. Thebalancer 125 has a hollow portion therein. The balancer 125 is providedto attenuate vibration caused by maldistribution of laundry. Thebalancer 125 may store a fluid such as salt water occupying 40% to 70%of the entire volume of the interior of the balancer 125. When the innertub 120 a is rotated with the laundry maldistributed at one side in theinner tub 120 a, the balancer 125 cancels vibration of the inner tubassembly 120 caused by maldistribution of the laundry, by causing thefluid in the balancer 125 to move to a position opposite to the positionof the objects in the resonance region of the inner tub 120 a.

The circulation duct 126 is provided to circulate wash water through theinner tub assembly 120.

The circulation duct 126 is connected to the inner tub assembly 120 toprovide a circulation flow channel 126 a for raising wash water from thelower portion of the inner tub assembly 120 to the upper portion of theinner tub assembly 120 and resupplying and circulating the same into theinner tub assembly 120.

The circulation duct 126 may be mounted on the inner circumferentialsurface of the inner tub assembly 120 in the form of a cover. The backsurface of the circulation duct 126 is open, and the side end of thecirculation duct 126 may be formed through curling or be curved. Theback surface of the curling portion is provided with a fastening lug,and the circulation duct 126 may be fastened to the innercircumferential surface of the inner tub assembly 120 by the fasteninglug. The inner circumferential surface of the inner tub assembly 120 maybe provided with a slit vertically elongated to allow the fastening lugto be fastened to the inner circumferential surface of the inner tubassembly 120 therethrough. An O-ring formed of rubber may be installedon the back surface of the circulation duct along the edge of the openportion of the circulation duct, thereby sealing the space between thecirculation duct and the inner tub. A space (flow channel) allowing washwater to rise therethrough is formed in the circulation duct 126.

The wash water discharge portion 127 is connected to a lower portion ofthe circulation duct 126. The wash water discharge portion 127 is apassage for receiving wash water discharged from the base by the blade123 and moving the same to the circulation duct 126.

The wash water discharge portion 127 is disposed at an outer lowerportion of the round portion 121 a of the base 121. The wash waterdischarge portion 127 includes a discharge body 127 a, a wash waterdischarge port formed at a lower portion of the discharge body 127 a anda duct communication port formed at an upper portion of the dischargebody 127 a.

The discharge body 127 a may be formed to be round. Thereby, when washwater moves from the blade 123 to the circulation duct 126, the movementdirection thereof may be smoothly switched from the radial direction tothe vertical direction. The upper surface of the discharge body 127 amay be further provided with a support extending upward so as to beconnected with the first step portion 121 b and the round portion 121 a.As the angled portion between the round portion 121 a and second stepportion 121 c is supported by the support, the strength of the structuremay be maintained.

The wash water discharge port is formed to face the outercircumferential portion of the blade 123, and the duct communicationport is formed to face the lower end of the circulation duct 126. Thesecond step portion 121 c is provided with a first communication hole121 c through which water pumped by the blade 123 is discharged. Thebase 121 forms, in the second step portion 121 c, the firstcommunication hole 121 c allowing the wash water discharge port tocommunication with the outer circumferential portion of the blade 123.The base 121 forms, in the round portion 121 a, a second communicationhole 121 a 2 allowing the duct communication port to communicate withthe lower end of the circulation duct 126. Wash water pumped by theblade 123 is introduced into the discharge body 127 a through the firstcommunication hole 121 c and the wash water discharge port. The washwater introduced into the discharge body 127 a may rise to thecirculation flow channel 126 a through the duct communication port andsecond communication hole 121 a 2.

The filter unit 128 may be installed at the upper end of the circulationduct 126.

The filter unit 128 includes a filter housing 128 a and a filter with anet structure provided in the filter housing 128 a. The holes of the netare very small. For example, the diameter of the holes of the net has asize of a few μm to a few hundred μm, small enough to filter out allfine lint from the laundry. In the case of the pulsator 122-type washingmachine for washing laundry through the rubbing operation, a lot ofimpurities including lint may be separated from the laundry. In thiscase, as wash water containing lint passes through the filter,impurities including the lint may be removed from the wash water. If thelint is not filtered out by the filter, the lint may be stuck to theinterior of the inner tub assembly 120. As a result, the lint may stickto the laundry again in the rinsing and dehydration operations.

One side of the filter housing 128 a communicates with the upper end ofthe circulation duct 126, and the other side of the filter housing 128 acommunicates with the interior of the inner tub assembly 120. The outlet128 a 1 is formed in the opposite lateral surface of the filter housing128 a. The outlet 128 a 1 may have a small vertical height and a largehorizontal width. Thereby, pumped wash water may be sprayed onto a widearea in the inner tub assembly 120.

Referring to FIGS. 5 and 6, the pulsator 122, the jig 146 and the blade123 may be disposed spaced from each other in the vertical direction inan overlapping manner so as not interfere with each other. For example,they may be disposed spaced 4 mm from each other. The pulsator 122 maybe disposed to be rotatable with respect to the jig 146, and blade 123may be disposed to be rotatable with respect to the jig 146. The jig 146is fixed to the base 121 of the inner tub assembly 120 in washing andrinsing.

The power transmission unit 140 includes a gearbox housing 141, a sungear 142, a planetary gears 143, a carrier 144, and a ring gear 145.

The gearbox housing 141 may include an upper housing 141 a and a lowerhousing 141 b. The upper and lower housings 141 a and 141 b may bedetachably coupled to each other. The upper housing and the lowerhousing 141 b are disposed at an upper and lower positions to face eachother. A first fastening portion 141 a 1 having the shape of a flangewith a large diameter is formed at the outer edge of the upper housing141 a, and a second fastening portion 141 b 1 having the shape of aflange with a large diameter is formed at the outer edge of the lowerhousing 141 b. The first fastening portion 141 a 1 and second fasteningportion 141 b 1 are disposed to overlapping each other in the verticaldirection in which thickness is defined and fastened to each other by afastening member.

The gearbox housing 141 is provided with a ring gear accommodationgroove 145 a having a cross-section of a square bracket shape at theinterior thereof. The ring gear accommodation groove 145 a is open tothe inside such that a portion of the ring gear 145 is insertedthereinto. The ring gear accommodation groove 145 a may be formed bycoupling between a first accommodation grooved formed in the upperhousing 141 a and a second accommodation groove formed in the lowerhousing. When the ring gear 145 is inserted into the ring gearaccommodation groove 145 a, vertical rotation of the ring gear 145 isrestricted by the ring gear accommodation groove 145 a. In addition, thering gear accommodation groove 145 a is provided with a plurality ofring gear rotation preventing lugs 145 b to restrict rotation of thering gear 145. The ring gear rotation preventing lugs 145 b may beformed on the inner circumferential surface of the ring gearaccommodation groove 145 a to face the outer circumferential surface ofthe ring gear 145, or formed on the upper surface or lower surface ofthe ring gear accommodation groove 145 a to face the upper surface orlower surface of the ring gear 145. A plurality of ring gear rotationpreventing grooves 145 c is formed on the outer circumferential surfaceof the ring gear 145 to face the ring gear rotation preventing lugs 145b. Thereby, rotation of the ring gear 145 is restricted as the ring gearrotation preventing lugs 145 b are inserted into the ring gear rotationpreventing grooves 145 c.

The sun gear 142 is rotatably provided in the gearbox housing 141. Thepower transmission unit 140 is connected to the washing shaft 132 a,which extends through the lower surface of the gearbox housing 141, andthus receives rotational power of the drive motor 130 from the washingshaft 132 a. The sun gear 142 integrally rotates with the washing shaft132 a. To transmit power from the washing shaft 132 a, a plurality oflugs such as serrations may be formed along the circumferential surfaceof the washing shaft 132 a, and a plurality of lugs may also be formedon the inner circumferential surface of the sun gear 142 to engage withthe serrations. As the washing shaft 132 a is coupled with the sun gear142 through the center portion of the sun gear 142, the sun gear 142rotates about the washing shaft 132 a. A plurality of gear teeth isformed along the outer circumferential surface of the sun gear 142.

A plurality of planetary gears 143 is engaged with the outercircumferential surface of the sun gear 142. Each of the planetary gears143 has a plurality of gear teeth on the outer circumferential surfacethereof. The planetary gears 143 may be disposed spaced from each otherin a circumferential direction. The planetary gears 143 spaced from eachother may be connected to the carrier 144 via a connection shaft 144 a.The planetary gears 143 are disposed between the sun gear 142 and thering gear 145 such that the gear teeth of the planetary gears 143 areengaged with the gear teeth of the sun gear 142 and the ring gear 145.Thereby, the planetary gears 143 performs rotation and revolution. Thedirection of rotation of the planetary gears 143 is opposite to thedirection of rotation of the sun gear 142. To allow the planetary gears143 to revolve around sun gear 142, the ring gear 145 is fixed. Thedirection of revolution of the planetary gears 143 is identical to thedirection of rotation of the sun gear 142.

The ring gear 145 is provided with a plurality of gear teeth along theinner circumferential surface thereof so as to be engaged with the gearteeth on the outer circumferential surface of the planetary gears 143.

The carrier 144 connects the planetary gears 143 via the connectionshaft 144 a. The connection shaft 144 a is coupled to the planetarygears 143 by vertically penetrating the planetary gears 143, and carrier144 connects the upper surface and lower surface of the connection shaft144 a.

One side of the carrier 144 may be connected to the connection shaft 144a so as to cover the upper surface or lower surface of the connectionshaft 144 a. The other side of the carrier 144 is provided with an upperconnection shaft 144 c for transmitting power to the pulsator 122. Theupper connection shaft 144 c is disposed on the washing shaft 132 a suchthat the upper connection shaft 144 c is positioned on the same verticalline as the washing shaft 132 a. However, the upper connection shaft 144c and the washing shaft 132 a rotate independently.

The upper connection shaft 144 c extends to the outside through theupper surface of the upper housing 141 a. The upper connection shaft 144c is connected to the pulsator 122. Thereby, torque increased ordecreased by the power transmission unit 140 is transmitted to thepulsator 122 via the carrier 144 and the upper connection shaft 144 c.

A power transmission cap 144 c may be mounted on the upper connectionshaft 144 so as to surround the exterior of the upper connection shaft144 c. The outer circumferential surface of the power transmission cap144 c has a lug structure such as a serration, and the powertransmission cap 144 c is mounted to an upper portion of the upperconnection shaft 144 c such that the upper connection shaft 144 c andthe power transmission cap 144 c overlap in the axial direction. Thecenter projection 122 b of the pulsator 122 is mounted on the powertransmission cap 144 c such that the center projection 122 b and thepower transmission cap 144 c overlap in the axial direction. Thepulsator 122, the power transmission cap 144 c, and the upper connectionshaft 144 c are fastened to each other by a fastening member 144 b 1such as a bolt. Thereby, the rotational power transmitted from thecarrier 144 is transmitted to the pulsator 122.

The upper connection shaft 144 c is supported by a first bearing 147 ainserted into the upper surface of the gearbox housing 141, and rotateswith respect to the gearbox housing 141.

The carrier 144 may include an upper carrier 1441 connecting the upperportions of the planetary gears 143 and a lower carrier 1442 forconnecting the lower portions of the planetary gears 143. The uppercarrier 1441 and the lower carrier 1442 are connected to each other soas to integrally rotate. A second bearing 147 b is provided between theinner side surface of the upper carrier 1441 and the upper surface ofthe sun gear 142, and a fourth bearing 147 d is provided between theinner side surface of the lower carrier 1442 and the lower surface ofthe sun gear 142. Thereby, the carrier 144 and the upper connectionshaft 144 c are supported so as to rotate independently with respect tothe washing shaft 132 a and the sun gear 142.

Referring to FIG. 7, the lower housing 141 b of the gearbox housing 141is inserted into the center coupling portion 146 a of the jig 146, andthus mounted to the jig 146. The first fastening portion 141 a 1 of theupper housing 141 a, the second fastening portion 141 b 1 of the lowerhousing 141 b and the center coupling portion 146 a of the jig 146 aredisposed to overlap each other in the thickness direction.

To fastened the gearbox housing 141 and the jig 146, a coupling portion141 c is formed on the lower surface of the second fastening portion 141b 1 in a protruding manner, and two or more coupling holes 146 a 1 areformed in the center coupling portion 146 a of the jig 146 such that thecoupling portion 141 c is inserted into. In addition, fastening holesmay be formed in the coupling portions of the gearbox housing and thejig, and a fastening member may be fastened to the gearbox housing andthe changed by penetrating the coupling portions. Thereby, the gearboxhousing and the jig may be fastened to each other. The coupling portionsmay have a diameter greater than that of the fastening member, therebyincreasing the strength of fastening between the gearbox housing and thejig. In addition, when the coupling portions are inserted into thecoupling holes, the gearbox housing is fixedly seated on the jig.Accordingly, connectivity of the fastening member may be enhanced inperforming the fastening operation.

Referring to FIG. 8A, the second step portion 121 c of the base 121 isformed to be stepped vertically upward with respect to the bottomsurface of the inner tub assembly 120. The second step portion 121 c isspaced a predetermined distance from the outer circumferential portionof the blade 123 so as to face the outer circumferential portion of theblade 123 while surrounding the outer circumferential portion of theblade 123.

Referring to FIG. 8B, the first step portion 121 b of the base 121 isformed to be stepped vertically upward with respect to the bottomsurface and the seating surface 121 d of the inner tub assembly 120. Thefirst step portion 121 b is spaced a predetermined distance from theouter circumferential portion of the jig 146 and the outercircumferential portion of the pulsator 122 so as to face the outercircumferential portions of the jig 146 and the pulsator 122 whilesurrounding the outer circumferential portion of the pulsator 122.Thereby, gaps formed between the first step portion 121 b, inner tubassembly 120, and jig 146 are narrow, and thus foreign substances suchas a coin may be prevented from being inserted thereinto even without aseparate cover provided in the base 121.

Referring to FIGS. 9A and 9B, a first fastening hole is formed in an endof each extension 146 b of the jig 146, and a second fastening hole isformed in the seating surface 121 d of the base 121. In addition, afastening groove is formed in the nut portion 127 b 1 of the couplingmember 127 b of the wash water discharge portion 127, and a fasteningmember 127 b 3 is inserted into and fastened to the nut portion 127 b 1through the first and second fastening holes. Thereby, the jig 146 maybe easily connected to the base 121 by the nut portion 127 b 1integrated with the wash water discharge portion 127 even without aseparate nut.

Referring to FIG. 10, a plurality of projections 146 d protrudingdownward are formed on the bottom surface of the center coupling portion146 a of the jig 146. The projections 146 d may be continuously arrangedin the circumferential direction. An air gap 146 d 1 serving as a pocketis formed between the projections 146 d to allow air to easily leavetherethrough.

When water stored between the base 121 and the bottom surface of theouter tub 110 rises into the base, and the air in the center couplingportion 146 a of the jig 146 is caused to escape, the air gap 146 d 1serving as an air pocket delays escape of the air until the water levelrises to the air gap 146 d 1. At this time, air failing to escape pushesback water, thereby serving as a sealer that prevents components such asshafts from being immersed in water.

Hereinafter, a movement path of water will be described with referenceto FIG. 1.

Wash water is supplied into the outer tub 110 through a wash watersupply hose connected to the wash water supply unit. At this time, adetergent may be supplied from a detergent supply unit into the outertub 110, together with the wash water.

Wash water supplied into the outer tub 110 flows into the space betweenthe inner tub assembly 120 and the outer tub 110 and is thus stored in alower portion of the outer tub 110.

Wash water supplied into the lower portion of the outer tub 110 isintroduced into the base 121 through the wash water introduction holes124 a of the hub 124. The wash water introduced into the base is pumpedby the blade 123, and is spouted into the inner tub assembly 120 throughthe outlet 128 a 1 of the filter housing 128 a via the wash waterdischarge portion 127 and circulation duct 126.

Thereby, wash water spouted to an upper portion of the inner tubassembly 120 spreads out to easily soak laundry. In addition, wash watermay also be uniformly sprayed onto laundry which are floating on thewash water in the inner tub assembly. Accordingly, a detergent mayuniformly infiltrate into the laundry, and thus washing performance maybe improved.

After soaking the laundry, the wash water moves down to the bottomsurface of the inner tub assembly 120 through the through holes 122 a 1of the pulsator 122, or permeates the gap between the first step portion121 b of the base 121 and the pulsator 122, and then moves down to thebottom surface of the inner tub assembly 120.

The wash water having moved down to the bottom surface of the inner tubassembly 120 is pumped by the blade 123 again to circulate through theinner tub assembly 120.

Hereinafter, support structures of the pulsator 122, the powertransmission unit 140 and the like, and a power transmission mechanismwill be described with reference FIGS. 1 and 5.

The outer tub 110 is supported by the suspension bar 111 in a suspendingmanner so as to be suspended on the cabinet 100.

The motor casing 131 is fixed to a lower portion of the outer tub 110 bythe fixation bracket 133.

The rotation shaft 132 extends vertically upward to the bottom surfaceof the outer tub 110, and is rotatably supported with respect to theouter tub 110 by the bearings installed in a lower portion of the outertub 110. The washing shaft 132 a integrated with the upper portion ofthe rotation shaft 132 extends vertically upward, penetrating the centerportion of the hub 124.

The washing shaft 132 a is coupled to the shaft coupling portion 123 chaving a circular shape and protruding from the center portion of theblade 123. Thereby, the washing shaft 132 a transmits the rotationalpower of the drive motor 130 to the blade 123 without decreasing therotational speed. In addition, the washing shaft 132 a is arranged inthe direction of gravitation, and is coupled to the sun gear 142 bypassing through the bottom surface of the gearbox housing 141 of thepower transmission unit 140. The washing shaft 132 a axially supportsthe planetary gears 143 connected to the sun gear 142, the ring gear 145and carrier 144 connected to the planetary gears 143, and the gearboxhousing 141 connected to the carrier 144, and the like.

The upper connection shaft 144 c is disposed on the washing shaft 132 asuch that the upper connection shaft 144 c and washing shaft 132 a areplaced on the same straight line. However, the upper connection shaft144 c operates separately from the washing shaft 132 a. The upperconnection shaft 144 c is integrally provided to an upper portion of thecarrier 144. The upper connection shaft 144 c is inserted into theconcave groove 122 b 1 of the pulsator 122 through the powertransmission cap 144 c.

A shaft support groove 122 b 2 is concavely formed inside the concavegroove 122 b 1 of the pulsator 122. The power transmission cap 144 cplaced on top of the upper connection shaft 144 c is inserted into theshaft support groove 122 b 2. A serration lug is formed in the shaftsupport groove 122 b 2 so as to face the outer circumferential surfaceof the power transmission cap 144 c. Thereby, the shaft support groove122 b 2 is coupled with the power transmission cap 144 c in an engagingmanner. Thereby, the rotational power may be transmitted from the upperconnection shaft 144 c to the pulsator 122.

The pulsator 122 is axially supported by the upper connection shaft 144c.

The rotational power generated by the drive motor 130 is transmittedfrom the washing shaft 132 a to the blade 123, thereby rotating theblade 123 at the same revolutions per minute as the drive motor 130.Thereby, the blade 123 may rotate at a rotational speed, for example,300 rpm, and thus wash water may be pumped to rise and circulate fromthe base 121 up to the upper end of the inner tub 120 a. The circulatedwash water is easily mixed with the detergent. The wash water mixed withthe detergent uniformly soaks laundry even if the amount thereof issmall. Thereby, washing performance may be improved, and powerconsumption may be reduced.

In addition, the rotational power generated by the drive motor 130 istransmitted from the washing shaft 132 a to the sun gear 142 of thepower transmission unit 140, and torque increased by decreasing therotational speed of the drive motor 130 according to the gear ratioamong the sun gear 142, the planetary gears 143 and the ring gear 145 istransmitted to the pulsator 122 via the carrier 144, thereby rotatingthe pulsator 122. Thereby, it is possible to rotate the blade 123 andthe pulsator 122 at different numbers of revolutions per minute usingthe same drive motor 130. In particular, using deceleration of thepulsator 122 and the increased torque, the rotation load of the drivemotor 130 may be reduced, and wash water and laundry may be easilystirred. In addition, efficient power transmission of the drive motor130 may be implemented.

Hereinafter, the first to tenth embodiments will be described in detail,respectively.

Referring to FIGS. 11 to 16, the power transmission unit 140, 240, 340,440 according to the first to fourth embodiments includes a planetarygear module 140, 240, 340, 440. The planetary gear module 140, 240, 340,440 is provided to transmit power generated by the same drive motor 130to the pulsator 122 and the blade 123 to rotate the pulsator 122 and theblade 123 at different revolutions per minute. The planetary gear module140, 240, 340, 440 includes a sun gear 142, 242, 342, 442, a pluralityof planetary gears 143, 243, 343, 443, a ring gear 145, 245, 345, 445and carrier 144, 244, 344, 444. The planetary gear module 140, 240, 340,440 includes a gearbox housing 141, 241, 341, 441. The gearbox housing141, 241, 341, 441 accommodates the sun gear 142, 242, 342, 442, theplurality of planetary gears 143, 243, 343, 443, the ring gear 145, 245,345, 445 and the carrier 144, 244, 344, 444.

According to the first to fourth embodiments, the sun gear 142, 242,342, 442 is connected to washing shaft 132 a, 232 a, 332 a, 442 a toreceive power of the drive motor 130. The sun gear 142, 242, 342, 442 iscoupled with the washing shaft 132 a, 232 a, 332 a, 442 a. The washingshaft 132 a, 232 a, 332 a, 442 a is coupled with the sun gear 142, 242,342, 442 by passing through the center portion of the sun gear 142, 242,342, 442. The rotational power of the washing shaft 132 a, 232 a, 332 a,442 a is transmitted to the sun gear 142, 242, 342, 442. The rotationalspeed and rotation direction of sun gear 142, 242, 342, 442 areidentical to the rotational speed and rotation direction of the drivemotor 130. A plurality of grooves may be formed in one of the outercircumferential surface of the washing shaft 132 a, 232 a, 332 a, 442 aand the inner circumferential surface of the sun gear 142, 242, 342,442, and a plurality of lugs to be engaged with the grooves may beformed on the other one of the outer circumferential surface of thewashing shaft 132 a, 232 a, 332 a, 442 a and the inner circumferentialsurface of the sun gear 142, 242, 342, 442. The sun gear 142, 242, 342,442 rotates together with the washing shaft 132 a, 232 a, 332 a, 442 a.A plurality of gear teeth is formed on the outer circumferential surfaceof the sun gear 142, 242, 342, 442.

According to the first to fourth embodiments, the planetary gears 143,243, 343, 443 and the sun gear 142, 242, 342, 442 are coupled to eachother in a manner that the gear teeth thereof are engaged with eachother. The planetary gears 143, 243, 343, 443 are rotated by rotationalpower received from the sun gear 142, 242, 342, 442. The planetary gears143, 243, 343, 443 rotate about a connection shaft 144 a, 244 a, 344 a,444 a coupled therewith by vertically penetrating the center portions ofthe planetary gears 143, 243, 343, 443. The planetary gears 143, 243,343, 443 rotate in the direction opposite to the direction of rotationof the sun gear 142, 242, 342, 442. The planetary gears 143, 243, 343,443 are disposed spaced from each other along the circumference of thesun gear 142, 242, 342, 442.

According to the first to fourth embodiments, the ring gear 145, 245,345, 445 has a ring shape. A plurality of gear teeth is formed along theinner circumferential surface of the ring gear 145, 245, 345, 445. Theplurality of planetary gears 143, 243, 343, 443 is inscribed in the ringgear 145, 245, 345, 445. The ring gear 145, 245, 345, 445 surrounds theplurality of planetary gears 143, 243, 343, 443 and is engaged with theplanetary gears 143, 243, 343, 443. The outer side of the ring gear 145,245, 345, 445 is fixed to the gearbox housing 741, 841, 941, 1041.

According to the first to fourth embodiments, the carrier 144, 244, 344,444 is arranged such that the plurality of planetary gears 143, 243,343, 443 is placed between the upper surface and lower surface of thecarrier 144, 244, 344, 444. The carrier 144, 244, 344, 444 includes aconnection shaft 144 a, 244 a, 344 a, 444 a rotatably connecting theplanetary gears 143, 243, 343, 443. The connection shaft 144 a, 244 a,344 a, 444 a penetrates the center portion of the planetary gears 143,243, 343, 443. The number of the provided connection shafts 144 a, 244a, 344 a, 444 a is equal to the number of the planetary gears 143, 243,343, 443. The connection shafts 144 a, 244 a, 344 a, 444 a are arrangedbetween the upper surface and lower surface of the carrier 144, 244,344, 444. The upper ends of the connection shafts 144 a, 244 a, 344 a,444 a are coupled to the upper surface of the carrier 144, 244, 344,444. The lower ends of the connection shafts 144 a, 244 a, 344 a, 444 aare coupled to the lower surface of the carrier 144, 244, 344, 444. Theconnection shafts 144 a, 244 a, 344 a, 444 a serve to support theplanetary gears 143, 243, 343, 443 such that the planetary gears 143,243, 343, 443 rotate around the sun gear 142, 242, 342, 442 in thecircumferential direction, keeping a predetermined distance from eachother.

Hereinafter, the power transmission unit 140 according to the firstembodiment will be described in detail with reference to FIGS. 11 and13.

In the first embodiment, the rotational speed of the pulsator 122 islower than the rotational speed of the blade 123. The power transmissionunit 140 transmits power of the drive motor 130 to the pulsator 122 suchthat the rotational speed of the pulsator 122 is lower than therotational speed of the drive motor 130. The power transmission unit 140transmits power to the blade 123 such that the rotational speed of thedrive motor 130 is equal to the rotational speed of the blade 123. Forexample, the pulsator 122 may be rotated at a speed within the rangebetween 100 rpm and 120 rpm, and the blade 123 may be rotated at a speedwithin the range between 280 rpm and 320 rpm. For example, revolutionsper minute of the drive motor 130 may be 300 rpm. By decreasing therotational speed of the pulsator 122, the rotation load of the drivemotor 130 may be reduced. That is, due to decrease in rotational speedof the carrier 144, torque transmitted to the pulsator 122 increases.Due to the increased torque, the pulsator 122 may apply less load to thedrive motor 130 than the blade 123 even if a relatively large amount ofwater and soaked laundry is rotated. By the rotational speed of theblade 123 higher than the rotational speed of the pulsator 122, apumping pressure for pumping water up to the upper end of the inner tubassembly 120 along the circulation duct 126 and a pumping speed of washwater may be sufficiently secured.

In the first embodiment, the direction of rotation of the pulsator 122is identical to the direction of rotation of the blade 123. That is, thedirection of rotation of the washing shaft 132 a, the direction ofrotation of the sun gear 142, the direction of rotation of the blade123, the direction of revolution of the planetary gears 143, and thedirection of rotation of the pulsator 122 are the same.

The inner side surface of the gearbox housing 141 is provided with aring gear accommodation groove for accommodating the ring gear 145. Thering gear 145 is inserted into and fixed to the ring gear accommodationgroove.

The gearbox housing 141 is fixed to the inner tub assembly 120 by thejig 146. The jig 146 is disposed to connect the outer circumferentialportion of the gearbox housing 141 to the base 121. The jig 146 includesa center portion having a ring shape. The jig 146 includes a pluralityof extensions radially extending from the center portion toward thebase. A coupling portion is formed on the outer circumferential portionof the gearbox housing 141. The coupling portion of the gearbox housing141 is coupled to the center portion of the jig 146. The center portionof the jig 146 and the outer circumferential portion of the gearboxhousing 141 are fastened to each other by a fastening member. Theextensions of the jig 146 may be fastened to the base 121 by a fasteningmember such as a bolt.

The ring gear 145 is fixed to the gearbox housing 141. A plurality oflugs is formed on one of the gearbox housing 141 and the ring gear 145,and a plurality of ring gear accommodation grooves 145 a to be engagedwith the lugs is formed on the other one of the gearbox housing 141 andthe ring gear 145. Referring to FIG. 13, the ring gear accommodationgrooves 145 a are formed in the outer circumferential surface of thering gear 145, and spaced a certain distance from each other in acircumferential direction. The lugs are formed on the innercircumferential surface of the gearbox housing 141 at a predetermineddistance from each other in the circumferential direction. The lugs areinserted into and coupled with the ring gear accommodation grooves 145a. Alternatively, the lugs may be formed on the outer circumferentialsurface of the ring gear 145, and the ring gear accommodation grooves145 a may be formed on the inner side surface of the gearbox housing141. The ring gear 145 is fixed to the inner tub assembly 120 by the jig146.

As the ring gear 145 is fixed to the inner tub assembly 120, theplanetary gears 143 revolves along the inner circumferential surface ofthe ring gear 145, while being engaged with the ring gear 145. Theplanetary gears 143 revolve around the sun gear 142. The direction ofrevolution of the planetary gears 143 is identical to the direction ofrotation of the sun gear 142. Revolutions per minute according torevolution of the plurality of planetary gears 143 may be set accordingto the gear ratio between the ring gear 145 and sun gear 142.Revolutions per minute of the carrier 144 are the same as revolutionsper minute according to revolution of the plurality of planetary gears143. Revolutions per minute of the carrier 144 are determined by thegear ratio between the ring gear 145 and the sun gear 142 andrevolutions per minute of the sun gear 142.

The carrier 144 forms the upper connection shaft 144 b. The upperconnection shaft 144 b integrally rotates with the carrier 144. Theupper connection shaft 144 b is inserted into and coupled with the shaftsupport groove 122 b 2 formed at the center of the bottom surface of thepulsator 122. The upper connection shaft 144 b transmits power to thepulsator 122.

The carrier 144 includes a power transmission cap 144 c disposed betweenthe upper connection shaft 144 b and the shaft support groove 122 b 2.The upper connection shaft 144 c is inserted and coupled between theupper connection shaft 144 b and the shaft support groove 122 b 2. Theinterior of the power transmission cap 144 c is provided with a couplingportion allowing the upper connection shaft 144 b to be press-fittedthereinto. Serration lugs for transmitting rotational power are formedon the outer circumferential surface of the power transmission cap 144c.

The blade 123 is directly connected to the drive motor 130, and thusrotates at the same speed as the drive motor 130 in the same directionof rotation as the drive motor 130. The center portion of the blade 123is provided with a shaft coupling portion 123 c. The washing shaft 132a, which is directly connected to the drive motor 130, is coupled to theshaft coupling portion 123 c.

The pulsator 122 receives rotational power through the upper connectionshaft 144 b of the carrier 144. The upper connection shaft 144 b isvertically disposed at an upper portion of the washing shaft 132 a. Theupper connection shaft 144 b and washing shaft 132 a rotateindependently. The speed of the pulsator 122 is decreased according tothe gear ratio of the planetary gear module 140.

The planetary gear module 140 includes a plurality of bearings 147 a,147 b, 147 c, which enable washing shaft 132 a, carrier 144 and gearboxhousing 141 to rotate relative to each other. A first bearing 147 a maybe installed between the upper surface of the gearbox housing 141 andthe upper connection shaft 144 b. Thereby, the upper connection shaft144 b may rotate relative to the gearbox housing 141. A second bearing147 b may be installed between the inner surface of the carrier 144 andthe washing shaft 132 a. Thereby, the washing shaft 132 a may rotateindependently from the carrier 144. A plurality of second bearings 147 bmay be provided. The second bearings 147 b may be spaced from each otherin the vertical direction. A third bearing 147 c may be installedbetween the inner surface of the gearbox housing 141 and the outer sidesurface of the carrier 144. Thereby, the carrier 144 may rotate relativeto the gearbox housing 141.

Referring to FIGS. 12 and 13, the second embodiment has the followingdifferences from the first embodiment: i) the rotational speed of thepulsator 122 is decreased below the rotational speed of the blade 123(the rotational speed of the pulsator 122 is lower than the rotationalspeed of the blade 123); ii) the pulsator 122 integrally rotates withthe washing shaft 232 a, and the blade 123 integrally rotates with thecarrier 244; iii) the carrier 244 need not include either an upperconnection shaft or a power transmission cap.

Hereinafter, a power transmission unit 240 according to the secondembodiment will be described in detail.

In the second embodiment, the rotational speed of the blade 123 is lowerthan the rotational speed of the pulsator 122. The power transmissionunit 240 transmits power to the blade 123 such that the rotational speedof the blade 123 is lower than the rotational speed of the drive motor130. The power transmission unit 240 transmits power to the pulsator 122such that the rotational speed of the drive motor 130 is equal to therotational speed of the pulsator 122. For example, the blade 123 may berotated at a speed within the range between 100 rpm and 120 rpm, and thepulsator 122 may be rotated at a speed within the range between 280 rpmand 320 rpm. For example, revolutions per minute of the drive motor 130may be 300 rpm. The planetary gear module transmits, to the blade 123,torque increased by reducing the rotational speed of the drive motor130.

In the second embodiment, the direction of rotation of the pulsator 122is identical to the direction of rotation of the blade 123. That is, thedirection of rotation of the washing shaft 232 a, the direction ofrotation of the sun gear 242, the direction of rotation of the pulsator122, the direction of revolution of the planetary gear 243, and thedirection of rotation of the blade 123 are the same.

The inner side surface of the gearbox housing 241 is provided with aring gear accommodation groove for accommodating the ring gear 245. Thering gear 245 is fixed to the ring gear accommodation groove by beinginserted into the ring gear accommodation groove.

The gearbox housing 241 is fixed to the inner tub assembly 120 by thejig 146. The jig 146 is disposed to connect the outer circumferentialportion of the gearbox housing 241 to the base 121. The jig 146 includesa center portion having a ring shape. The jig 146 includes a pluralityof extensions radially extending from the center portion toward thebase. A coupling portion is formed on the outer circumferential portionof the gearbox housing 241. The coupling portion of the gearbox housing241 is coupled to the center portion of the jig 146. The center portionof the jig 146 and the outer circumferential portion of the gearboxhousing 241 are fastened to each other by a fastening member. Theextensions of the jig 146 may be fastened to the base 121 by a fasteningmember such as a bolt.

The ring gear 245 is fixed to the gearbox housing 141. In order totransmit rotational power of the ring gear 245 to the gearbox housing241, a plurality of lugs is formed on one of the gearbox housing 241 andthe ring gear 245, and a plurality of lug accommodation grooves 245 a tobe engaged with the lugs is formed on the other one of the gearboxhousing 241 and the ring gear 245. Referring to FIG. 13, the lugaccommodation grooves 245 a are formed on the outer circumferentialsurface of the ring gear 245, and spaced a certain distance from eachother in a circumferential direction. The lugs are formed on the innercircumferential surface of the gearbox housing 241 at a predetermineddistance from each other in the circumferential direction. The lugs areinserted into and coupled with the lug accommodation grooves 245 a.Alternatively, the lugs may be formed on the outer circumferentialsurface of the ring gear 245, and the lug accommodation grooves 245 amay be formed on the inner side surface of the gearbox housing 241. Thering gear 245 is fixed to the inner tub assembly 120 by the jig 146.

As the ring gear 245 is fixed to the inner tub assembly 120, theplanetary gear 243 revolves along the inner circumferential surface ofthe ring gear 245, while being engaged with the ring gear 245. Theplanetary gear 243 revolves around the sun gear 242. The direction ofrevolution of the planetary gear 243 is identical to the direction ofrotation of the sun gear 242. Revolutions per minute according torevolution of the plurality of planetary gear 243 may be set accordingto the gear ratio between the ring gear 245 and sun gear 242.Revolutions per minute of the carrier 244 are equal to revelations perminute according to revolution of the plurality of planetary gear 243.Revolutions per minute of the carrier 244 are determined by the gearratio between the ring gear 245 and sun gear 242 and revolutions perminute of the sun gear 242.

The blade 123 is rotated by the rotational power transmitted from thecarrier 244. The rotational speed of the blade 123 is decreasedaccording to the gear ratio between the sun gear 242 and ring gear 245.The carrier 244 is coupled to the center portion of the inner tubassembly 120. The blade 123 is coupled to the lower portion of thecarrier 244. The blade 123 integrally rotates with the carrier 244. Aplurality of lugs and a plurality of lug accommodation grooves may beprovided to the boundary surfaces between the carrier 244 and blade 123.The plurality of lugs is disposed to face the plurality of lugaccommodation grooves. The rotational power received by the carrier 244is transmitted to the blade 123. The lugs or lug accommodation groovesmay be formed on the carrier 244, and the lug accommodation grooves orthe lugs may be formed on the blade 123.

The pulsator 122 is directly connected to the drive motor 130, and thusrotates at the same speed as the drive motor 130 in the same directionof rotation as the drive motor 130. The washing shaft 232 a is directlyconnected to the pulsator 122. The pulsator 122 receives power of thedrive motor 130 via the washing shaft 232 a. The washing shaft 232 apenetrates the gearbox housing 241. The washing shaft 232 a verticallyextends up to the shaft support groove 122 b 2 of the pulsator 122. Theupper portion of the washing shaft 232 a is coupled to the pulsator 122.

The planetary gear module 240 includes a plurality of bearings 247 a,247 b, 247 c, 247 d, which enable the washing shaft 232 a, carrier 244and gearbox housing 241 to rotate relative to each other. A firstbearing 247 a may be installed between the upper surface of the gearboxhousing 241 and the washing shaft 232 a. Thereby, the washing shaft 232a may rotate relative to the gearbox housing 241. A second bearing 247 bmay be installed between the inner surface of the carrier 244 and thewashing shaft 232 a. Thereby, the washing shaft 232 a may rotateindependently from the carrier 244. A third bearing 247 c may beinstalled between the inner surface of the gearbox housing 241 and theouter side surface of the carrier 244. Thereby, the carrier 244 mayrotate relative to the gearbox housing 241. A fourth bearing 247 d maybe installed between the inner side surface of the blade 123 and thewashing shaft 232 a. Thereby, the blade 123 may rotate relative to thewashing shaft 232 a.

Referring to FIGS. 14 and 15, the third embodiment has the followingdifferences from the first embodiment: i) the rotational speed of thepulsator 122 is lower than the rotational speed of the blade 123; ii)the direction of rotation of the pulsator 122 is opposite to thedirection of rotation of the blade 123; iii) the pulsator 122 integrallyrotates with the washing shaft 332 a, and the blade 123 integrallyrotates with the ring gear 345; iv) the carrier 244 need not includeeither an upper connection shaft or a power transmission cap; the jig146 is not needed; vi) the carrier 344 is fixed to the inner tubassembly 120.

Hereinafter, a power transmission unit 340 according to the thirdembodiment will be described in detail.

In the third embodiment, the rotational speed of the blade 123 is lowerthan the rotational speed of the pulsator 122. The power transmissionunit 340 transmits power to the blade 123 such that the rotational speedof the blade 123 is lower than the rotational speed of the drive motor130. The power transmission unit 340 transmits power to the pulsator 122such that the rotational speed of the drive motor 130 is equal to therotational speed of the pulsator 122. For example, the blade 123 may berotated at a speed within the range between 100 rpm and 120 rpm, and thepulsator 122 may be rotated at a speed within the range between 280 rpmand 320 rpm. For example, revolutions per minute of the drive motor 130may be 300 rpm. The planetary gear module transmits, to the blade 123,torque increased by reducing the rotational speed of the drive motor130.

In the third embodiment, the direction of rotation of the pulsator 122is opposite to the direction of rotation of the blade 123. The powertransmission unit 340 transmits power such that the direction ofrotation of the pulsator 122 is opposite to the direction of rotation ofthe blade 123. The direction of rotation of the washing shaft 332 a, thedirection of rotation of the sun gear 342, and the direction of rotationof the pulsator 122 are the same. The direction of rotation of the ringgear 345 is the same as the direction of rotation of the blade 123. Thedirection of rotation of the washing shaft 332 a, the sun gear 342 andpulsator 122 is opposite to the direction of rotation of the ring gear345 and blade 123. The pulsator 122 and the blade 123 rotate in theopposite directions, and wash water and the detergent introduced intothe lower portion of the inner tub assembly 120 through the wash waterintroduction holes in the hub 124 are easily mixed by the stirringoperation of the blade 123. According, washing performance may beimproved. In addition, in the case where laundry on the pulsator 122 areconcentrated at one position in the inner tub 120 a, if washing isperformed solely by rotation of the pulsator 122, vibration develops inthe inner tub assembly 120. However, if the blade 123 rotates in thedirection opposite to the direction of rotation of the pulsator 122, theexciting force generated by the pulsator 122 may be reduced. This effectis the same as the effect of vibration attenuation according to theprinciple of the gyro effect. The gyro effect refers to a tendency of abody of rotation rotating at a high speed to uniformly maintain the axisof rotation thereof.

The inner side surface of the gearbox housing 341 is provided with aring gear accommodation groove for accommodating the ring gear 345. Thering gear 345 is fixed to the ring gear accommodation groove by beinginserted into the ring gear accommodation groove.

The gearbox housing 341 is not fixed to the inner tub assembly 120. Thegearbox housing 341 rotates relative to the inner tub assembly 120.

The carrier 344 is fixed to the inner tub assembly 120. The carrier 344is fixed to the hub 324. The carrier 344 is coupled to the centerportion of the hub 324. A plurality of lugs and a plurality of lugaccommodation grooves are formed between the carrier 344 and hub 124.Thereby, the carrier 344 is fixed by the hub 124.

The ring gear 345 is fixed to the gearbox housing 341. In order totransmit rotational power of the ring gear 345 to the gearbox housing341, a plurality of lugs is formed on one of the gearbox housing 341 andthe ring gear 345, and a plurality of lug accommodation grooves 345 a tobe engaged with the lugs is formed on the other one of the gearboxhousing 341 and the ring gear 345. Referring to FIG. 16, the lugaccommodation grooves 345 a are formed on the outer circumferentialsurface of the ring gear 345, and spaced a certain distance from eachother in a circumferential direction. The lugs are formed on the innercircumferential surface of the gearbox housing 341 at a predetermineddistance from each other in the circumferential direction. The lugs areinserted into and coupled with the lug accommodation grooves 345 a.Alternatively, the lugs may be formed on the outer circumferentialsurface of the ring gear 345, and the lug accommodation grooves 345 amay be formed on the inner side surface of the gearbox housing 341.

The gearbox housing 341 and the ring gear 345 rotate. The gearboxhousing 341 and the ring gear 345 rotate relative to the inner tubassembly 120. A jig 146 for fixing the ring gear 345 need not beprovided between pulsator 122 and blade 123. As the carrier 344 is fixedto the inner tub assembly 120, the ring gear 345 rotates around theplanetary gears 343 while being engaged with the planetary gears 343.The ring gear 345 rotates about the sun gear 342. The direction ofrotation of the ring gear 345 is opposite to the direction of rotationof the sun gear 342, and is identical to the direction of rotation ofthe planetary gears 343. Revolutions per minute of the ring gear 345 aredetermined by the gear ratio between the ring gear 345 and sun gear 342and revolutions per minute of the sun gear 342.

The blade 123 is rotated by the rotational power transmitted from thegearbox housing 341. Rotation of the blade 123 is decreased according tothe gear ratio between the sun gear 342 and ring gear 345. The gearboxhousing 341 is coupled to the center portion of the blade 123. The blade123 is coupled to the lower portion of the gearbox housing 341. Theblade 123 integrally rotates with the gearbox housing 341. The blade 123integrally rotates with the ring gear 345. A plurality of lugs and aplurality of lug accommodation grooves may be provided to the boundarysurfaces between the gearbox housing 341 and blade 123. The plurality oflugs is disposed to face the plurality of lug accommodation grooves. Therotational power received by the gearbox housing 341 is transmitted tothe blade 123. The lugs or lug accommodation grooves may be formed onthe gearbox housing 341, and the lug accommodation grooves or the lugsmay be formed on the blade 123.

The pulsator 122 is directly connected to the drive motor 130, and thusrotates at the same speed as the drive motor 130 and in the samedirection of rotation as the drive motor 130. The washing shaft 232 a isdirectly connected to the pulsator 122. The pulsator 122 receives powerof the drive motor 130 via the washing shaft 232 a. The washing shaft232 a penetrates the gearbox housing 241. The washing shaft 232 avertically extends up to the shaft support groove 122 b 2 of thepulsator 122. The upper portion of the washing shaft 232 a is coupled tothe pulsator 122.

The planetary gear module 340 includes a plurality of bearings 347 a,347 b, 347 c which enable the washing shaft 332 a, carrier 344 andgearbox housing 341 to rotate relative to each other. A first bearing347 a may be inserted and installed between the upper surface of thegearbox housing 341 and washing shaft 332 a. Thereby, the washing shaft332 a and the gearbox housing 341 may rotate independently at differentrevolutions per minute. A second bearing 347 b may be inserted andinstalled between the carrier 344 and the washing shaft 332 a. Thereby,the washing shaft 332 a may rotate relative to the carrier 344. A thirdbearing 347 c may be inserted and installed between the gearbox housing341 and the carrier 344. Thereby, the gearbox housing 341 may rotaterelative to the carrier 344.

Referring to FIGS. 15 and 16, the fourth embodiment has the followingdifferences from the first embodiment: i) the direction of rotation ofthe pulsator 122 is opposite to the direction of rotation of the blade123; ii) the pulsator 122 integrally rotates with the ring gear 345, andthe blade 123 integrally rotates with the washing shift 442 a; iii) thegearbox housing 441 fixes the carrier 444, rather than fixing the ringgear 445; iv) the ring gear 445 is fixed, and a support member 448rotating relative to the gearbox housing 441 is separately provided; v)the upper connection shaft 448 b and the power transmission cap 448 care formed on the support member 448, rather than on the carrier 444.

Hereinafter, a power transmission unit 440 according to the fourthembodiment will be described in detail.

In the fourth embodiment, the rotational speed of the pulsator 122 islower than the rotational speed of the blade 123. The power transmissionunit 440 transmits power to the pulsator 122 such that the rotationalspeed of the pulsator 122 is lower than the rotational speed of thedrive motor 130. The power transmission unit 440 transmits power to theblade 123 such that the rotational speed of the drive motor 130 is equalto the rotational speed of the blade 123. For example, the pulsator 122may be rotated at a speed within the range between 100 rpm and 120 rpm,and the blade 123 may be rotated at a speed within the range between 280rpm and 320 rpm. For example, revolutions per minute of the drive motor130 may be 300 rpm. The resulting effect is the same as the effect ofthe first embodiment.

In the fourth embodiment, the direction of rotation of the pulsator 122is opposite to the direction of rotation of the blade 123. The powertransmission unit 440 transmits power such that the direction ofrotation of the pulsator 122 is opposite to the direction of rotation ofthe blade 123. The direction of rotation of the washing shaft 432 a, thedirection of rotation of the sun gear 442, and the direction of rotationof the blade 123 are the same. The direction of rotation of the ringgear 445 is the same as the direction of rotation of the pulsator 122.The direction of rotation of the washing shaft 432 a, the sun gear 442and blade 123 is opposite to the direction of rotation of the ring gear445 and pulsator 122. The resulting effect is the same as the effect ofthe third embodiment.

The planetary gear module 440 includes a support member 448. The supportmember 448 is disposed in the gearbox housing 441. The support member448 is a separate member rotating independently from the gearbox housing441. The planetary gear module 440 rotates relative to the gearboxhousing 441. A ring gear accommodation groove for accommodating the ringgear 445 is provided in the inner side surface of the planetary gearmodule 440. The planetary gear module 440 is inserted into and fixed tothe ring gear accommodation groove.

The gearbox housing 441 fixes the carrier 444. The jig 146 fixes thegearbox housing 441 to the inner tub assembly 120. The carrier 444 isfixed to the inner tub assembly 120 by the gearbox housing 441 and jig146.

The gearbox housing 441 is fixed by the jig 146. The jig 146 is disposedto connect the outer circumferential portion of the gearbox housing 441to the inner tub assembly 120. The jig 146 includes a center portionhaving a ring shape. The jig 146 includes a plurality of extensionsradially extending from the center portion toward the base. A couplingportion is formed on the outer circumferential portion of the gearboxhousing 441. The coupling portion of the gearbox housing 441 is coupledto the center portion of the jig 146. The center portion of the jig 146and the outer circumferential portion of the gearbox housing 441 arefastened to each other by a fastening member. The extensions of the jig146 may be fastened to the base 121 by a fastening member such as abolt.

The ring gear 445 is fixed to the support member 448. In order totransmit rotational power of the ring gear 445 to the support member448, a plurality of lugs is formed on one of the support member 448 andthe ring gear 445, and a plurality of lug accommodation grooves 445 a tobe engaged with the lugs is formed on the other one of the supportmember 448 and the ring gear 445. Referring to FIG. 16, the lugaccommodation grooves 445 a are formed on the outer circumferentialsurface of the ring gear 445, and spaced a certain distance from eachother in a circumferential direction. The lugs are formed on the innercircumferential surface of the support member 448 at a predetermineddistance from each other in the circumferential direction. The lugs areinserted into and coupled with the lug accommodation grooves 445 a.Alternatively, the lugs may be formed on the outer circumferentialsurface of the ring gear 445, and the lug accommodation grooves 445 amay be formed on the inner side surface of the support member 448.

The ring gear 445 and the support member 448 rotate. The support member448 and the ring gear 445 rotate relative to the inner tub assembly 120.The jig 146 disposed between the pulsator 122 and the blade 123 does notfix the ring gear 445. As the carrier 444 is fixed to the inner tubassembly 120, the ring gear 445 rotates around the planetary gears 443while being engaged with the planetary gears 443. The ring gear 445rotates about the sun gear 442. The direction of rotation of the ringgear 445 is opposite to the direction of rotation of the sun gear 442,and is identical to the direction of rotation of the planetary gears443. Revolutions per minute of the ring gear 445 are determined by thegear ratio between the ring gear 445 and sun gear 442 and revolutionsper minute of the sun gear 442.

The support member 448 forms the upper connection shaft 448 b. The upperconnection shaft 448 b integrally rotates with the support member 448.The upper connection shaft 448 b is inserted into and coupled with theshaft support groove 122 b 2 formed at the center of the bottom surfaceof the pulsator 122. The upper connection shaft 448 b transmits power tothe pulsator 122.

The support member 448 includes a power transmission cap 448 c disposedbetween the upper connection shaft 448 b and the shaft support groove122 b 2. The power transmission cap 448 c is inserted and coupledbetween the upper connection shaft 448 b and the shaft support groove122 b 2. The interior of the power transmission cap 448 c is providedwith a coupling portion allowing the upper connection shaft 448 b to bepress-fitted thereinto. Serration lugs for transmitting rotational powerare formed on the outer circumferential surface of the powertransmission cap 448 c.

The blade 123 is directly connected to the drive motor 130, and thusrotates at the same speed as the drive motor 130 and in the samedirection of rotation as the drive motor 130. The center portion of theblade 123 is provided with a shaft coupling portion 123 c. The washingshaft 432 a, which is directly connected to the drive motor 130, iscoupled to the shaft coupling portion 123 c.

The pulsator 122 receives rotational power through the upper connectionshaft 448 b of the support member 448. The upper connection shaft 448 bis vertically disposed at an upper portion of the washing shaft 432 a.The upper connection shaft 448 b and the washing shaft 432 a rotateindependently. The rotational speed of the pulsator 122 is decreasedaccording to the gear ratio of the planetary gear module 440.

The planetary gear module 440 includes a plurality of bearings 447 a,447 b, 447 c which enable the washing shaft 432 a, carrier 444 andsupport member 448 to rotate relative to each other. A first bearing 447a may be installed between the upper portion of the gearbox housing 441and upper connection shaft 448 b of the support member 448. Thereby, theupper connection shaft 448 b may rotate relative to the gearbox housing441. A second bearing 447 b may be installed between the inner surfaceof the carrier 444 and the washing shaft 432 a. Thereby, the washingshaft 432 a may rotate independently from the carrier 444. A pluralityof second bearings 447 b may be provided. The second bearings 447 b maybe spaced from each other in the vertical direction. A third bearing 447c may be installed between the inner side surface of the support member448 and the outer side surface of the carrier 444. Thereby, the supportmember 448 may rotate relative to the carrier 444.

Referring FIGS. 17A, 17B, 18A, 18B and 19, the power transmission unit540, 640 according to the fifth and sixth embodiments includes aplurality of bevel gears. The plurality of bevel gears according to thefifth and sixth embodiments is rotatably provided in the gearbox housing541, 641. The plurality of bevel gears includes a first bevel gear 5421,6421 and a third bevel gear 5423, 6423, whose axes of rotation arearranged in the vertical direction. The plurality of bevel gearsincludes a plurality of second bevel gears 5422, 6422, whose axes ofrotation are arranged in the horizontal direction. Herein, thehorizontal direction is the direction parallel with the surface of washwater, and the vertical direction is a direction identical to orparallel with the direction of gravitation.

Referring FIGS. 17A, 17B, 18A, 18B and 19, the first bevel gear 5421,6421 according to the fifth and sixth embodiments integrally rotateswith the washing shaft 532 a, 632 a. The first bevel gear 5421, 6421 isa truncated conical gear. The first bevel gear 5421, 6421 includes abottom surface, an upper surface, and a lateral surface having adiameter decreasing from the bottom surface to the upper surface andconnecting the upper surface with the bottom surface. A plurality ofgear teeth is formed on the lateral surface of the first bevel gear5421, 6421. The inclination angle of the gear teeth of the first bevelgear 5421, 6421 may be, for example, 45°, but embodiments of the presentinvention are not limited thereto. The washing shaft 532 a, 632 a servesas the rotation shaft of the first bevel gear 5421, 6421. The washingshaft 532 a, 632 a penetrates the bottom surface and upper surface ofthe first bevel gear 5421. The washing shaft 532 a, 632 a is coupledwith the center portion of the first bevel gear 5421. The first bevelgear 5421 is rotated about the washing shaft 532 a, 632 a by the powertransmitted from the drive motor 130. A plurality of lugs is formed onone of the first bevel gear 5421, 6421 and the washing shaft 532 a, 632a, and a plurality of lug accommodation grooves to be engaged with thelugs is formed on the other one of the first bevel gear 5421, 6421 andthe washing shaft 532 a, 632 a. Thereby, the rotational power of thedrive motor 130 is transmitted from the washing shaft 532 a, 632 a tothe first bevel gear 5421, 6421. The plurality of lugs may be formed onthe washing shaft 532 a, 632 a, and the plurality of lug accommodationgrooves may be formed on the first bevel gear 5421, 6421. The positionsof the plurality of lugs and the plurality of lug accommodation groovesmay be switched. The lugs are a position to face the lug accommodationgrooves. The first bevel gear 5421, 6421 rotates at the same speed asthe drive motor 130 and in the same direction of rotation as the drivemotor 130.

Referring FIGS. 17A, 17B, 18A, 18B and 19, the second bevel gears 5422,6422 according to the fifth and sixth embodiments is a truncated conicalgear. The rotation shaft 5422 a, 6422 a of the second bevel gears 5422,6422 is disposed perpendicular to the washing shaft 532 a, 632 a. Aplurality of second bevel gears 5422, 6422 may be provided. Theplurality of second bevel gears 5422, 6422 is engaged with the firstbevel gear 5421, 6421. The second bevel gears 5422, 6422 are disposed toface each other. The second bevel gears 5422, 6422 are disposed spacedfrom each other in the circumferential direction. Each of the secondbevel gears 5422, 6422 is provided with the rotation shaft 5422 a, 6422a. The second bevel gears 5422, 6422 rotate about the rotation shafts5422 a, 6422 a. The rotation shafts 5422 a, 6422 a of the second bevelgears 5422, 6422 are rotatably supported by a support member 543, 643.The support member 543, 643 includes a support body 543 a, 643 aextending around the washing shaft 532 a, 632 a in a circumferentialdirection. The support member 543, 643 includes a support portion 543 b,643 b protruding from the support body 543 a, 643 a toward the rotationshaft 5422 a, 6422 a. The support portion 543 b, 643 b protrudes fromthe support body 543 a, 643 a upward. A plurality of support portions543 b, 643 b may be provided. Each of the support portions 543 b, 643 bis provided with a shaft accommodation hole. Bearings may be mounted inthe shaft accommodation hole of each of the support portions 543 b, 643b, rotatably supporting the rotation shafts 5422 a, 6422 a.

Referring FIGS. 17A, 17B, 18A, 18B and 19, the third bevel gear 5423,6423 according to the fifth and sixth embodiments is a truncated conicalgear. The third bevel gear 5423, 6423 is disposed to face the firstbevel gear 5421, 6421. The third bevel gear 5423, 6423 is rotatablyprovided to the upper portion of the gearbox housing 541, 641. Aplurality of gear teeth is provided to the lateral surface of the thirdbevel gear 5423, 6423 so as to be engaged with the second bevel gears5422, 6422. The third bevel gear 5423, 6423 receives rotational powertransmitted from the second bevel gears 5422, 6422.

In the fifth and sixth embodiments, the blade 123 and the pulsator 122rotate at the same rotational speed. The power transmission unit 540,640 transmits power to the pulsator 122 such that the rotational speedof the drive motor 130 is equal to the rotational speed of the pulsator122. The power transmission unit 540, 640 transmits power to the blade123 such that the rotational speed of the drive motor 130 is equal tothe rotational speed of the blade 123. The blade 123 and the pulsator122 rotate at the same rotational speed as the drive motor 130. Thefirst bevel gear 5421, 6421 and the third bevel gear 5423, 6423 have thesame number of gear teeth. The gear ratio between the first bevel gear5421, 6421 and the third bevel gear 5423, 6423 is 1:1. The third bevelgear 5423 rotates at the same rotational speed as the first bevelgearing 5421.

In the fifth and sixth embodiments, the direction of rotation of theblade 123 is opposite to the direction of rotation of the pulsator 122.The power transmission unit 540, 640 transmits power such that thedirection of rotation of the pulsator 122 is opposite to the directionof rotation of the blade 123. As the blade 123 and pulsator 122 rotatein the opposite direction is, dissolution of the detergent may befurther enhanced, and vibration caused by the pulsator 122 due to massdistribution of laundry on the pulsator 122 may be attenuated.

Hereinafter, the power transmission unit 540 according to the fifthembodiment will be described in detail with reference to FIGS. 17A, 17B,and 19.

The gearbox housing 541 is not fixed to the inner tub assembly 120. Thegearbox housing 541 rotates relative to the inner tub assembly 120. Thegearbox housing 541 is disposed between the pulsator 122 and blade 123.The gearbox housing 541 is inserted into the concave groove 122 b 1 ofthe pulsator 122.

The support member 543 is fixed to the inner tub assembly 120. Thesupport member 543 is fixed to the hub 124. A center coupling portion124 b for coupling with the rotation shaft 5422 a of the drive motor 130is provided to the interior of the hub 124. The support member 543 isfixedly coupled with the center coupling portion 124 b of the hub 124.The lower side of the support body 543 a is fixed to the center couplingportion 124 b of the hub 124. The upper surface of the center couplingportion 124 b is coupled with the lower side of the support body 543 a.The inner circumferential surface of the center coupling portion 124 bof the hub 124 is provided with a plurality of lug grooves with whichgear teeth may be engaged. The support body 543 a accommodates the firstbevel gear 5421 in a surrounding manner. The support body 543 a isspaced from the first bevel gear 5421. The upper side of the supportbody 543 a is configured to connect the plurality of support portions543 b. The second bevel gear 5422 is supported by the support portions543 b. Thus, the second bevel gear 5422 does not revolve around thewashing shaft 532 a, but only rotates about the rotation shaft 5422 b.

The third bevel gear 5423 integrally rotates with the blade 123. Thethird bevel gear 5423 integrally rotates with the gearbox housing 541.The third bevel gear 5423 rotates relative to the washing shaft 532 b. Aplurality of lugs 5423 b is formed on one of the third bevel gear 5423and the gearbox housing 541, and a plurality of lug accommodationgrooves 5423 a to be engaged with the lugs 5423 b is formed on the otherone of the third bevel gear 5423 and the gearbox housing 541. The lugs5423 b may be formed on the third bevel gear 5423, and the lugaccommodation grooves 5423 a may be formed on the gearbox housing 541.The lugs 5423 b are inserted into and coupled with the lug accommodationgrooves 5423 a. The rotational power of the third bevel gear 5423 istransmitted to the gearbox housing 541. In order to transmit therotational power of the third bevel gear 5423 to the gearbox housing541, the lugs 5423 b are arranged to face the lug accommodation grooves5423 a. The positions of the plurality of lugs 5423 b and the pluralityof lug accommodation grooves 5423 a may be switched.

The blade 123 integrally rotates with the third bevel gear 5423. Theblade 123 receives power from the drive motor 130 via the third bevelgear 5423 and the gearbox housing 541. The outer circumferential portionof the gearbox housing 541 is coupled with the center portion of theblade 123. The rotational power of the third bevel gear 5423 istransmitted to the blade 123 via the gearbox housing 541. The blade 123rotates at the same rotational speed as the drive motor 130 in thedirection opposite to the direction of rotation of the drive motor 130.The direction of rotation of the blade 123 is opposite to the directionof rotation of the washing shaft 532 a.

The pulsator 122 integrally rotates with the first bevel gear 5421. Thepulsator 122 integrally rotates with the washing shaft 532 a. Thewashing shaft 532 a extends upward, penetrating the bottom surface ofthe gearbox housing 541. The washing shaft 532 a is coupled to the shaftsupport groove 122 b 2 of the pulsator 122. The pulsator 122 may befastened to the washing shaft 532 a by a fastening member such as itsgroove. The pulsator 122 receives power from the drive motor 130 via thewashing shaft 532 a. The washing shaft 532 a penetrates the third bevelgear 5423 as well as the first bevel gear 5421. The washing shaft 532 ais engaged with the first bevel gear 5421. The washing shaft 532 a isseparated from the third bevel gear 5423. The pulsator 122 rotates atthe same speed as the drive motor 130 and in the same direction ofrotation as the drive motor 130. The direction of rotation of thepulsator 122 is identical to the direction of rotation of the washingshaft 532 a.

The power transmission unit 540 includes a plurality of bearings 547 a,547 b, 547 c which enable the washing shaft 532 a, gearbox housing 541and center coupling portion 124 b to rotate relative to each other andenable the washing shaft 532 a, gearbox housing 541 and support member543 to rotate relative to each other. A first bearing 547 a may beinstalled between the upper portion of the gearbox housing 541 and thewashing shaft 532 a. The first bearing 547 a may be installed betweenthe center portion of the third bevel gear 5423 and washing shaft 532 a.The washing shaft 532 a is coupled to the inner circumferential surfaceof the first bearing 547 a. The first bearing 547 a enables the thirdbevel gear 5423 to rotate relative to the washing shaft 532 a. Thewashing shaft 532 a and the third bevel gear 5423 may rotateindependently. In addition, a second bearing 547 b is installed betweenthe inner circumferential surface of the gearbox housing 541 and theouter circumferential surface of the support body 543 a, and gearboxhousing 141 may rotate relative to the support body 543 a. In addition,a third bearing 547 c is installed between the center coupling portion124 b of the hub 124 and washing shaft 532 a. The washing shaft 532 a iscoupled to the inner circumferential surface of the third bearing 547 c.The washing shaft 532 a may rotate relative to the hub 124.

Referring to FIGS. 18A, 18B and 19, the sixth embodiment, which will bedescribed below, has the following differences from the fifthembodiment: i) the blade 123 integrally rotates with the washing shift442 a and a first bevel gear 6421, and the pulsator 122 integrallyrotates with the third bevel gear 6423 and an upper connection shaft 649b; ii) the gearbox housing 441 is fixed to the inner tub assembly 120 bythe jig 146, and fixes a support member 643; iii) a third bevel gearsupport member 649 coupled to a third bevel gear 6423 and rotatingrelative to the gearbox housing 441 is separately provided; iv) theupper connection shaft 448 b and the power transmission cap 448 c areformed on the support member 649.

Hereinafter, a power transmission unit 640 according to the sixthembodiment will be described in detail.

The gearbox housing 641 is fixed to the inner tub assembly 120. Thegearbox housing 641 is fixed to the inner tub assembly 120 by the jig146. The gearbox housing 641 is disposed between the pulsator 122 andblade 123. The gearbox housing 641 is inserted into the concave groove122 b 1 of the pulsator 122.

The gearbox housing 641 is fixed by the jig 146. The jig 146 is disposedto connect the outer circumferential portion of the gearbox housing 641to the base 121. The jig 146 includes a center portion having a ringshape. The jig 146 includes a plurality of extensions radially extendingfrom the center portion toward the base. A coupling portion is formed onthe outer circumferential portion of the gearbox housing 641. Thecoupling portion of the gearbox housing 641 is coupled to the centerportion of the jig 146. The center portion of the jig 146 and the outercircumferential portion of the gearbox housing 641 are fastened to eachother by a fastening member. The extensions of the jig 146 may befastened to the base 121 by a fastening member such as a bolt.

The support member 643 is fixed to the gearbox housing 641. The supportmember 643 is fixed to the inner tub assembly 120 by the gearbox housing641 and jig 146. The support body 643 a accommodates the first bevelgear 6421 in a surrounding manner. The support body 643 a is spaced fromthe first bevel gear 6421. The upper side of the support body 643 a isconfigured to connect the plurality of support portions 643 b. Thesecond bevel gear 6422 is supported by the support portions 643 b. Thus,the second bevel gear 6422 does not revolve around the washing shaft 632a, but only rotates about the rotation shaft 6422 b.

The third bevel gear 6423 integrally rotates with the pulsator 122. Thepower transmission unit 640 includes a support member 649. The supportmember 649 is disposed in the gearbox housing 641. The support member649 is a separate member rotating independently from the gearbox housing641. The support member 649 rotates relative to the gearbox housing 641.The support member 649 is fixedly coupled to the third bevel gear 6423.The third bevel gear 6423 integrally rotates with the support member649. The third bevel gear 6423 rotates relative to the washing shaft 632b. A plurality of lugs 6423 b is formed on one of the third bevel gear6423 and the support member 649, and a plurality of lug accommodationgrooves 6423 a to be engaged with the lugs 6423 b is formed on the otherone of the third bevel gear 6423 and the support member 649. The lugs6423 b may be formed on the third bevel gear 6423, and the lugaccommodation grooves 6423 a may be formed on the support member 649.The lugs 6423 b are inserted into and coupled with the lug accommodationgrooves 6423 a. The rotational power of the third bevel gear 6423 istransmitted to the support member 649. In order to transmit therotational power of the third bevel gear 6423 to the support member 649,the lugs 6423 b are arranged to face the lug accommodation grooves 6423a. The positions of the plurality of lugs 6423 b and the plurality oflug accommodation grooves 6423 a may be switched.

The support member 649 forms the upper connection shaft 649 b. The upperconnection shaft 649 b integrally rotates with the support member 649.The upper connection shaft 649 b is inserted into and coupled with theshaft support groove 122 b 2 formed at the center of the bottom surfaceof the pulsator 122. The upper connection shaft 649 b transmits power tothe pulsator 122.

The support member 649 includes a power transmission cap 649 c disposedbetween the upper connection shaft 649 b and the shaft support groove122 b 2. The power transmission cap 649 c is inserted and coupledbetween the upper connection shaft 649 b and the shaft support groove122 b 2. The interior of the power transmission cap 649 c is providedwith a coupling portion allowing the upper connection shaft 649 b to bepress-fitted thereinto. Serration lugs for transmitting rotational powerare formed on the outer circumferential surface of the powertransmission cap 649 c.

The blade 123 integrally rotates with the first bevel gear 6421. Theblade 123 receives power from the drive motor 130 via the washing shaft632 a and the first bevel gear 6421. The washing shaft 632 a extendsupward, penetrating the bottom surface of the gearbox housing 641. Thewashing shaft 632 a illustrates the first bevel gear 6421. The washingshaft 632 a is engaged with the first bevel gear 6421. The washing shaft632 a separated from the third bevel gear 6423. The blade 123 rotates atthe same rotational speed as the drive motor 130 in the same directionof rotation as the drive motor 130. The direction of rotation of theblade 123 is identical to the direction of rotation of the washing shaft632 a.

The pulsator 122 integrally rotates with the third bevel gear 6423. Thepulsator 122 integrally rotates with the upper connection shaft 649 b.The upper connection shaft 649 b is particularly disposed at an upperportion of the washing shaft 632 a. The upper connection shaft 649 b andthe washing shaft 632 a rotate independently. The pulsator 122 rotatesat the same speed as the drive motor 130 in the direction opposite tothe direction of rotation of the drive motor 130. The direction ofrotation of the pulsator 122 is opposite to the direction of rotation ofthe washing shaft 632 a.

The power transmission unit 640 includes a plurality of bearings 647 a,647 b, 647 c which enable the blade 123, gearbox housing 641 and upperconnection shaft 649 b to rotate relative to each other. A first bearing647 a is installed between the upper portion of the gearbox housing 641and the upper connection shaft 649 b. The upper connection shaft 649 bis coupled to the inner circumferential surface of the first bearing 647a. The first bearing 647 a enables the upper connection shaft 649 b torotate relative to the gearbox housing 641. The upper connection shaft649 b and the gearbox housing 641 may rotate independently. In addition,a second bearing 647 b is installed between the gearbox housing 641 andthe blade 123, and the base 121 may rotate relative to the gearboxhousing 141.

Referring to FIGS. 20A to 23, the power transmission unit 740, 840, 940,1040 according to the seventh to tenth embodiments includes a powertransmission unit 740, 840, 940, 1040 provided with a separate planetarygear set. The power transmission unit 740, 840, 940, 1040 may includedual gearboxes. The power transmission unit 740, 840, 940, 1040 areprovided to transmit power generated by the same drive motor 130 to thepulsator 122 and blade 123 to rotate the pulsator 122 and the blade 123at different revolutions per minute. The power transmission unit 740,840, 940, 1040 may decrease the rotational speed of the drive motor 130(e.g., 450 rpm) to two different rotational speeds (e.g., 300 rpm forthe blade 123 and 100 rpm for the pulsator 122) to transmit the rotationpower of the drive motor 130 to the pulsator 122 and the blade 123. Thepower transmission unit 740, 840, 940, 1040 transmits power of the drivemotor 130 to the pulsator 122 such that the rotational speed of thepulsator 122 is lower than the rotational speed of the drive motor 130.The power transmission unit 740, 840, 940, 1040 transmits power to theblade 123 such that the rotational speed of the blade 123 is lower thanthe rotational speed of the drive motor 130. The degree of decrease inthe rotational speed may be preset for each of the pulsator 122 and theblade 123 through the dual planetary gear module 740, 840, 940, 1040.

The dual planetary gear module 740, 840, 940, 1040 according to theseventh to tenth embodiments includes a first planetary gear module 740a, 840 a, 940 a, 1040 a provided to transmit rotational power to thepulsator 122 and a second planetary gear module 740 b, 840 b, 940 b,1040 b provided to transmit rotational power to the blade 123.

The planetary gear module 140, 440, 740 a, 840 a, 940 a, 1040 atransmits power to the pulsator 122 such that a rotational speed of thepulsator 122 is decreased. The planetary gear module 140, 440, 740 a,840 a, 940 a, 1040 a transmits power to the pulsator 122 such that arotational speed of the pulsator 122 is lower than a rotational speed ofthe drive motor 130.

The planetary gear module 240, 340, 740 b, 840 b, 940 b, 1040 btransmits power to the blade 123 such that a rotational speed of theblade 123 is decreased. The planetary gear module 240, 340, 740 b, 840b, 940 b, 1040 b transmits power to the blade 123 such that a rotationalspeed of the blade 123 is lower than a rotational speed of the drivemotor 130.

The first planetary gear module 740 a, 840 a, 940 a, 1040 a transmitspower to the pulsator 122 such that a rotational speed of the pulsator122 is decreased. The second planetary gear module 740 b, 840 b, 940 b,1040 b transmits power to the blade 123 such that a rotational speed ofthe blade 123 is decreased.

The first planetary gear module 740 a, 840 a, 940 a, 1040 a transmitspower to the pulsator 122 such that a rotational speed of the pulsator122 is lower than a rotational speed of the drive motor 130. The secondplanetary gear module 740 b, 840 b, 940 b, 1040 b transmits power to theblade 123 such that a rotational speed of the blade 123 is lower than arotational speed of the drive motor 130.

The first planetary gear module 740 a, 840 a, 940 a, 1040 a according tothe seventh to tenth embodiments includes a first sun gear 742 a, 842 a,942 a, 1042 a, a plurality of first planetary gears 743 a, 843 a, 943 a,1043 a, a first carrier 744 a, 844 a, 944 a, 1044 a, and a first ringgear 745 a, 845 a, 945 a, 1045 a. The first planetary gear module 740 a,840 a, 940 a, 1040 a includes a first gearbox housing 741 a, 841 a, 941a, 1041 a. The first gearbox housing 741 a, 841 a, 941 a, 1041 aaccommodates the first sun gear 742 a, 842 a, 942 a, 1042 a, theplurality of first planetary gears 743 a, 843 a, 943 a, 1043 a, thefirst carrier 744 a, 844 a, 944 a, 1044 a, and the first ring gear 745a, 845 a, 945 a, 1045 a. The first sun gear 742 a, 842 a, 942 a, 1042 a,the plurality of first planetary gears 743 a, 843 a, 943 a, 1043 a andthe first carrier 744 a, 844 a, 944 a, 1044 a are rotatably provided inthe first gearbox housing 741 a, 841 a, 941 a, 1041 a.

The second planetary gear module 740 b, 840 b, 940 b, 1040 b accordingto the seventh to tenth embodiments includes a second sun gear 742 b,842 b, 942 b, 1042 b, a plurality of second planetary gears 743 b, 843b, 943 b, 1043 b, a second carrier 744 b, 844 b, 944 b, 1044 b, and asecond ring gear 745 b, 845 b, 945 b, 1045 b. The second planetary gearmodule 740 b, 840 b, 940 b, 1040 b includes a second gearbox housing 741b, 841 b, 941 b, 1041 b. The second gearbox housing 741 b, 841 b, 941 b,1041 b accommodates the second sun gear 742 b, 842 b, 942 b, 1042 b, theplurality of second planetary gears 743 b, 843 b, 943 b, 1043 b, thesecond carrier 744 b, 844 b, 944 b, 1044 b, and the second ring gear 745b, 845 b, 945 b, 1045 b. The second sun gear 742 b, 842 b, 942 b, 1042b, the plurality of second planetary gears 743 b, 843 b, 943 b, 1043 band the second ring gear 745 b, 845 b, 945 b, 1045 b are rotatablyprovided in the second gearbox housing 741 b, 841 b, 941 b, 1041 b.

In the seventh to tenth embodiments, the first planetary gear module 740a, 840 a, 940 a, 1040 a is stacked on the second planetary gear module740 b, 840 b, 940 b, 1040 b. The first gearbox housing 741 a, 841 a, 941a, 1041 a may be inserted into the concave groove 122 b 1 of thepulsator 122.

In the seventh to tenth embodiments, the first sun gear 742 a, 842 a,942 a, 1042 a, the second sun gear 742 b, 842 b, 942 b, 1042 b and thewashing shaft 732 a, 832 a, 932 a, 1032 a rotate integrally.

According to the seventh to tenth embodiments, the first sun gear 742 a,842 a, 942 a, 1042 a is connected to the washing shaft 732 a, 832 a, 932a, 1032 a to receive power of the drive motor 130. The first sun gear742 a, 842 a, 942 a, 1042 a is coupled with the washing shaft 732 a, 832a, 932 a, 1032 a. The washing shaft 732 a, 832 a, 932 a, 1032 apenetrates the center portion of the first sun gear 742 a, 842 a, 942 a,1042 a. The rotational power of the washing shaft 732 a, 832 a, 932 a,1032 a is transmitted to the first sun gear 742 a, 842 a, 942 a, 1042 a.The first sun gear 742 a, 842 a, 942 a, 1042 a rotates at the same speedas the drive motor 130 in the same direction of rotation as the drivemotor 130. A plurality of groove may be formed on one of the outercircumferential surface of the washing shaft 732 a, 832 a, 932 a, 1032 aand the inner circumferential surface of the first sun gear 742 a, 842a, 942 a, 1042 a, and a plurality of lugs to be engaged with the groovesmay be formed on the other one of the outer circumferential surface ofthe washing shaft 732 a, 832 a, 932 a, 1032 a and the innercircumferential surface of the first sun gear 742 a, 842 a, 942 a, 1042a. The first sun gear 742 a, 842 a, 942 a, 1042 a rotates together withthe washing shaft 732 a, 832 a, 932 a, 1032 a. A plurality of heat if heis formed on the outer circumferential surface of the first sun gear 742a, 842 a, 942 a, 1042 a.

According to the seventh to tenth embodiments, the second sun gear 742b, 842 b, 942 b, 1042 b is connected to the washing shaft 732 a, 832 a,932 a, 1032 a to receive power of the drive motor 130. The second sungear 742 b, 842 b, 942 b, 1042 b is coupled with the washing shaft 732a, 832 a, 932 a, 1032 a. The washing shaft 732 a, 832 a, 932 a, 1032 apenetrates the center portion of the second sun gear 742 b, 842 b, 942b, 1042 b. The rotational power of the washing shaft 732 a, 832 a, 932a, 1032 a is transmitted to the second sun gear 742 b, 842 b, 942 b,1042 b. The second sun gear 742 b, 842 b, 942 b, 1042 b at the samerotational speed as the drive motor 130 in the same direction ofrotation as the drive motor 130. A plurality of grooves may be formed inone of the outer circumferential surface of the washing shaft 732 a, 832a, 932 a, 1032 a and the inner circumferential surface of the second sungear 742 b, 842 b, 942 b, 1042 b, and a plurality of lugs to be engagedwith the grooves may be formed on the other one of the outercircumferential surface of the washing shaft 732 a, 832 a, 932 a, 1032 aand the inner circumferential surface of the second sun gear 742 b, 842b, 942 b, 1042 b. The second sun gear 742 b, 842 b, 942 b, 1042 brotates together with the washing shaft 732 a, 832 a, 932 a, 1032 a. Aplurality of gear teeth is formed on the outer circumferential surfaceof the second sun gear 742 b, 842 b, 942 b, 1042 b.

According to the seventh to tenth embodiments, the plurality of firstplanetary gears 743 a, 843 a, 943 a, 1043 a is coupled to the first sungear 742 a, 842 a, 942 a, 1042 a such that such that the gear teeththereof are engaged with each other. The first planetary gears 743 a,843 a, 943 a, 1043 a rotate by rotational power received from the firstsun gear 742 a, 842 a, 942 a, 1042 a. The first planetary gears 743 a,843 a, 943 a, 1043 a rotate about a connection shaft 744 a 1, 844 a 1,944 a 1, 1044 a 1 coupled therewith by vertically penetrating the centerportions of the first planetary gears 743 a, 843 a, 943 a, 1043 a. Thefirst planetary gears 743 a, 843 a, 943 a, 1043 a rotate in thedirection opposite to the direction of rotation of the first sun gear742 a, 842 a, 942 a, 1042 a. The first planetary gears 743 a, 843 a, 943a, 1043 a are disposed spaced from each other along the circumference ofthe first sun gear 742 a, 842 a, 942 a, 1042 a.

According to the seventh to tenth embodiments, the first ring gear 745a, 845 a, 945 a, 1045 a has a ring shape. A plurality of gear teeth isformed along the inner circumferential surface of the first ring gear745 a, 845 a, 945 a, 1045 a. The plurality of first planetary gears 743a, 843 a, 943 a, 1043 a is inscribed in the first ring gear 745 a, 845a, 945 a, 1045 a. The first ring gear 745 a, 845 a, 945 a, 1045 asurrounds the plurality of first planetary gears 743 a, 843 a, 943 a,1043 a and engages with the first planetary gears 743 a, 843 a, 943 a,1043 a. The outer side of the first ring gear 745 a, 845 a, 945 a, 1045a is fixed to the first gearbox housing 741 a, 841 a, 941 a, 1041 a.

According to the seventh to tenth embodiments, the first carrier 744 a,844 a, 944 a, 1044 a is arranged such that the plurality of firstplanetary gears 743 a, 843 a, 943 a, 1043 a is placed between the uppersurface and lower surface of the first carrier 744 a, 844 a, 944 a, 1044a. The first carrier 744 a, 844 a, 944 a, 1044 a includes a connectionshaft 744 a 1, 844 a 1, 944 a 1, 1044 a 1 rotatably connecting the firstplanetary gears 743 a, 843 a, 943 a, 1043 a. The connection shaft 744 a1, 844 a 1, 944 a 1, 1044 a 1 penetrates the center portion of the firstplanetary gears 743 a, 843 a, 943 a, 1043 a. The number of the providedconnection shaft 744 a 1, 844 a 1, 944 a 1, 1044 a 1 is equal to thenumber of the first planetary gears 743 a, 843 a, 943 a, 1043 a. Theconnection shaft 744 a 1, 844 a 1, 944 a 1, 1044 a 1 are arrangedbetween the upper surface and lower surface of the carrier 144, 244,344, 444. The upper ends of the connection shaft 744 a 1, 844 a 1, 944 a1, 1044 a 1 are coupled to the upper surface of the first carrier 744 a,844 a, 944 a, 1044 a. The lower ends of the connection shaft 744 a 1,844 a 1, 944 a 1, 1044 a 1 are coupled to the lower surface of the firstcarrier 744 a, 844 a, 944 a, 1044 a. The connection shaft 744 a 1, 844 a1, 944 a 1, 1044 a 1 serve to support the first planetary gears 743 a,843 a, 943 a, 1043 a such that the first planetary gears 743 a, 843 a,943 a, 1043 a rotate around the first sun gear 742 a, 842 a, 942 a, 1042a in the circumferential direction, keeping a predetermined distancefrom each other.

According to the seventh to tenth embodiments, the plurality of secondplanetary gears 743 b, 843 b, 943 b, 1043 b is coupled to the second sungear 742 b, 842 b, 942 b, 1042 b such that such that the gear teeththereof are engaged with each other. The second planetary gears 743 b,843 b, 943 b, 1043 b rotate by rotational power received from the secondsun gear 742 b, 842 b, 942 b, 1042 b. The second planetary gears 743 b,843 b, 943 b, 1043 b rotate about a connection shaft 744 a 1, 844 a 1,944 a 1, 1044 a 1 coupled therewith by vertically penetrating the centerportions of the second planetary gears 743 b, 843 b, 943 b, 1043 b. Thesecond planetary gears 743 b, 843 b, 943 b, 1043 b rotate in thedirection opposite to the direction of rotation of the second sun gear742 b, 842 b, 942 b, 1042 b. The second planetary gears 743 b, 843 b,943 b, 1043 b are disposed spaced from each other along thecircumference of the second sun gear 742 b, 842 b, 942 b, 1042 b.

According to the seventh to tenth embodiments, the second ring gear 745b, 845 b, 945 b, 1045 b has a ring shape. A plurality of gear teeth isformed along the inner circumferential surface of the second ring gear745 b, 845 b, 945 b, 1045 b. The plurality of second planetary gears 743b, 843 b, 943 b, 1043 b is inscribed in the second ring gear 745 b, 845b, 945 b, 1045 b. The second ring gear 745 b, 845 b, 945 b, 1045 bsurrounds the plurality of second planetary gears 743 b, 843 b, 943 b,1043 b and engages with the second planetary gears 743 b, 843 b, 943 b,1043 b. The outer side of the second ring gear 745 b, 845 b, 945 b, 1045b is fixed to the second gearbox housing 741 b, 841 b, 941 b, 1041 b.

According to the seventh to tenth embodiments, the second carrier 744 b,844 b, 944 b, 1044 b is arranged such that the plurality of secondplanetary gears 743 b, 843 b, 943 b, 1043 b is placed between the uppersurface and lower surface of the second carrier 744 b, 844 b, 944 b,1044 b. The second carrier 744 b, 844 b, 944 b, 1044 b includes a secondplanetary gear connection shaft 744 b 1, 844 b 1, 944 b 1, 1044 b 1rotatably connecting the second planetary gears 743 b, 843 b, 943 b,1043 b. The second planetary gear connection shaft 744 b 1, 844 b 1, 944b 1, 1044 b 1 penetrates the center portion of the second planetarygears 743 b, 843 b, 943 b, 1043 b. The number of the provided secondplanetary gear connection shaft 744 b 1, 844 b 1, 944 b 1, 1044 b 1 isequal to the number of the second planetary gears 743 b, 843 b, 943 b,1043 b. The second planetary gear connection shaft 744 b 1, 844 b 1, 944b 1, 1044 b 1 are arranged between the upper surface and lower surfaceof the carrier 144, 244, 344, 444. The upper ends of the secondplanetary gear connection shaft 744 b 1, 844 b 1, 944 b 1, 1044 b 1 arecoupled to the upper surface of the second carrier 744 b, 844 b, 944 b,1044 b. The lower ends of the second planetary gear connection shaft 744b 1, 844 b 1, 944 b 1, 1044 b 1 are coupled to the lower surface of thesecond carrier 744 b, 844 b, 944 b, 1044 b. The second planetary gearconnection shaft 744 b 1, 844 b 1, 944 b 1, 1044 b 1 serve to supportthe second planetary gears 743 b, 843 b, 943 b, 1043 b such that thesecond planetary gears 743 b, 843 b, 943 b, 1043 b rotate around thesecond sun gear 742 b, 842 b, 942 b, 1042 b in the circumferentialdirection, keeping a predetermined distance from each other.

In the seventh to tenth embodiments, one of the first carrier 744 a, 844a, 944 a, 1044 a and the first ring gear 745 a, 845 a, 945 a, 1045 a isfixed to one of the second carrier 744 b, 844 b, 944 b, 1044 b and thesecond ring gear 745 b, 845 b, 945 b, 1045 b. One of the first carrier744 a, 844 a, 944 a, 1044 a and the first ring gear 745 a, 845 a, 945 a,1045 a is fixed to inner tub assembly 120. One of the second carrier 744b, 844 b, 944 b, 1044 b and the second ring gear 745 b, 845 b, 945 b,1045 b is fixed to the inner tub assembly 120.

In the seventh to tenth embodiments, the pulsator 122 integrally rotateswith one of the first carrier 744 a, 844 a, 944 a, 1044 a and the firstring gear 745 a, 845 a, 945 a, 1045 a. Revolutions per minute of thepulsator 122 are determined by the gear ratio between the first ringgear 745 a, 845 a, 945 a, 1045 a and the first sun gear 742 a, 842 a,942 a, 1042 a and revolutions per minute of the first sun gear 742 a,842 a, 942 a, 1042 a.

In the seventh to tenth embodiments, the blade 123 integrally rotateswith one of the second carrier 744 b, 844 b, 944 b, 1044 b and thesecond ring gear 745 b, 845 b, 945 b, 1045 b. Revolutions per minute ofthe blade 123 are determined by the gear ratio between the second ringgear 745 b, 845 b, 945 b, 1045 b and the second sun gear 742 b, 842 b,942 b, 1042 b and revolutions per minute of the second sun gear 742 b,842 b, 942 b, 1042 b.

Since the second sun gear 742 b, 842 b, 942 b, 1042 b and the first sungear 742 a, 842 a, 942 a, 1042 a have the same revolutions per minute asthe washing shaft 732 a, 832 a, 932 a, 1032 a, The degree of decrease inthe rotational speed of the pulsator 122 may be set to be different fromthat of the blade 123 by setting a first gear ratio between the firstring gear 745 a, 845 a, 945 a, 1045 a and the first sun gear 742 a, 842a, 942 a, 1042 a to be different from a second gear ratio between thesecond ring gear 745 b, 845 b, 945 b, 1045 b and the second sun gear 742b, 842 b, 942 b, 1042 b.

Hereinafter, a power transmission unit 740 according to the seventhembodiment will be described in detail with reference to FIGS. 20A, 20Band 20C.

In the seventh embodiment, the direction of rotation of the pulsator 122is opposite to the direction of rotation of the blade 123. The powertransmission unit 740 transmits power such that the direction ofrotation of the pulsator 122 is opposite to the direction of rotation ofthe blade 123. The direction of rotation of the washing shaft 732 a, thedirection of rotation of the first sun gear 742 a, the direction ofrotation of the second sun gear 742 b, the direction of revolution ofthe first planetary gear 743 a, and the direction of rotation of thepulsator 122 are the same. The direction of rotation of the blade 123 isidentical to the direction of rotation of the second ring gear 745 b.The direction of rotation of the pulsator 122 is identical to thedirection of rotation of the drive motor 130. The direction of rotationof the blade 123 is opposite to the direction of rotation of the drivemotor 130. The resulting effect is the same as the effect of the thirdembodiment.

A ring gear accommodation groove is provided to the interior of thefirst gearbox housing 741 a. The first ring gear 745 a is inserted intoand fixed to the ring gear accommodation groove of the first gearboxhousing 741 a.

A ring gear accommodation groove is provided to the interior of thesecond gearbox housing 741 b. The second ring gear 745 b is insertedinto and fixed to the ring gear accommodation groove of the secondgearbox housing 741 b.

The first ring gear 745 a and the second carrier 744 b are fixed by eachother. The second carrier 744 b is fixed to the inner tub assembly 120.The lower portion of the second carrier 744 b is fixed to the hub 124.The first ring gear 745 a is fixed to the inner tub assembly 120 by thesecond carrier 744 b. That is, the first ring gear 745 a, the secondcarrier 744 b and the inner tub assembly 120 do not make a rotationrelative to each other.

The first ring gear 745 a is fixed to the first gearbox housing 741 a. Aplurality of lugs is formed on one of the first gearbox housing 741 aand the first ring gear 745 a, and a plurality of lug accommodationgrooves to be engaged with the lugs is formed on the other one of thefirst gearbox housing 741 a and the first ring gear 745 a. The lugaccommodation grooves may be formed in the outer circumferential surfaceof the first ring gear 745 a, and spaced a certain distance from eachother in a circumferential direction. The lugs may be formed on theinner circumferential surface of the first gearbox housing 741 a at apredetermined distance from each other in the circumferential direction.The lugs are inserted into and coupled with the lug accommodationgrooves. Alternatively, the lugs may be formed on the outercircumferential surface of the first ring gear 745 a, and the lugaccommodation grooves may be formed in the inner side surface of thefirst gearbox housing 741 a. The lugs and the lug accommodation groovesprevent the first ring gear 745 a from rotating relative to the firstgearbox housing 741 a. The first ring gear 745 a is fixed to the innertub assembly 120 by the second carrier 744 b. In order to fix the firstring gear 745 a to the inner tub assembly 120, the first gearbox housing741 a is connected and fixed to the second carrier 744 b.

As the first ring gear 745 a is fixed to the inner tub assembly 120, thefirst planetary gear 743 a revolves along the inner circumferentialsurface of the first ring gear 745 a, while being engaged with the firstring gear 745 a. The first planetary gear 743 a revolves around thefirst sun gear 742 a. The direction of revolution of the first planetarygear 743 a is identical to the direction of rotation of the first sungear 742 a. Revolutions per minute according to revolution of theplurality of first planetary gear 743 a may be set according to the gearratio between the first ring gear 745 a and the first sun gear 742 a.Revolutions per minute of the first carrier 744 a are equal torevelations per minute according to revolution of the plurality of firstplanetary gear 743 a. Revolutions per minute of the first carrier 744 aare determined by the gear ratio between the first ring gear 745 a andthe first sun gear 742 a and revolutions per minute of the first sungear 742 a.

The first carrier 744 a forms the upper connection shaft 744 a 2. Theupper connection shaft 744 a 2 integrally rotates with the first carrier744 a. The upper connection shaft 744 a 2 is inserted into and coupledwith the shaft support groove 122 b 2 formed at the center of the bottomsurface of the pulsator 122. The upper connection shaft 744 a 2transmits power to the pulsator 122.

The first carrier 744 a includes a power transmission cap 744 c disposedbetween the upper connection shaft 744 a 2 and the shaft support groove122 b 2. The power transmission cap 744 c is inserted and coupledbetween the upper connection shaft 744 a 2 and the shaft support groove122 b 2. The interior of the power transmission cap 744 c is providedwith a coupling portion allowing the upper connection shaft 144 b to bepress-fitted thereinto. Serration lugs for transmitting rotational powerare formed on the outer circumferential surface of the powertransmission cap 744 c.

The second gearbox housing 741 b is not fixed to the inner tub assembly120. The second gearbox housing 741 b rotates relative to the inner tubassembly 120.

The second carrier 744 b is fixed to the inner tub assembly 120. Thesecond carrier 744 b is fixed to the hub 124. The second carrier 744 bis coupled to the center portion of the hub 124. A plurality of lugs anda plurality of lug accommodation grooves are formed between the secondcarrier 744 b and hub 124. Thereby, the second carrier 744 b is fixed bythe hub 124.

The second ring gear 745 b is fixed to the second gearbox housing 741 b.In order to transmit rotational power of the second ring gear 745 b tothe second gearbox housing 741 b, a plurality of lugs is formed on oneof the second gearbox housing 741 b and the second ring gear 745 b, anda plurality of lug accommodation grooves to be engaged with the lugs isformed on the other one of the second gearbox housing 741 b and thesecond ring gear 745 b. The lug accommodation grooves are formed on theouter circumferential surface of the second ring gear 745 b, and spaceda certain distance from each other in a circumferential direction. Thelugs are formed on the inner circumferential surface of the secondgearbox housing 741 b at a predetermined distance from each other in thecircumferential direction. The lugs are inserted into and coupled withthe lug accommodation grooves. Alternatively, the lugs may be formed onthe outer circumferential surface of the second ring gear 745 b, and thelug accommodation grooves may be formed on the inner side surface of thesecond gearbox housing 74 lb.

The second gearbox housing 741 b and the second ring gear 745 b rotate.The second gearbox housing 741 b and the second ring gear 745 b rotaterelative to the inner tub assembly 120. A jig 146 for fixing the secondring gear 745 b need not be provided between pulsator 122 and blade 123.As the second carrier 744 b is fixed to the inner tub assembly 120, thesecond ring gear 745 b rotates around the second planetary gear 743 bwhile being engaged with the second planetary gear 743 b. The secondring gear 745 b rotates about the second sun gear 342 b. The directionof rotation of the second ring gear 745 b is opposite to the directionof rotation of the second sun gear 342 b, and is identical to thedirection of rotation of the second planetary gear 743 b. Revolutionsper minute of the second ring gear 745 b are determined by the gearratio between the second ring gear 745 b and second sun gear 342 b andrevolutions per minute of the second sun gear 342 b.

The blade 123 is rotated by the rotational power transmitted from thesecond gearbox housing 74 lb. The second gearbox housing 741 b iscoupled with the center portion of the blade 123. The blade 123integrally rotates with the second gearbox housing 741 b. The blade 123integrally rotates with the second ring gear 745 b. A plurality of lugsand a plurality of lug accommodation grooves may be provided to theboundary surfaces between the second gearbox housing 741 b and blade123. The plurality of lugs is disposed to face the plurality of lugaccommodation grooves. The rotational power received by the secondgearbox housing 741 b is transmitted to the blade 123. The lugs or lugaccommodation grooves may be formed on the second gearbox housing 741 b,and the lug accommodation grooves or the lugs may be formed on the blade123. The direction of rotation of the blade 123 is opposite to thedirection of rotation of the drive motor 130.

The pulsator 122 receives rotational power through the upper connectionshaft 744 a 2 of the first carrier 744 a. The upper connection shaft 744a 2 is vertically disposed at an upper portion of the washing shaft 732a. The upper connection shaft 744 a 2 and the washing shaft 732 a rotateindependently. The direction of rotation of the pulsator 122 isidentical to the direction of rotation of the drive motor 130.

The power transmission unit 740 includes a plurality of bearings 747 a,747 b, 747 c, 747 d, 747 e, 747 f, which enable the washing shaft 732 a,upper connection shaft 744 a 2, first carrier 744 a and first gearboxhousing 741 a to rotate relative to each other. A first bearing 747 amay be inserted and installed between the first gearbox housing 741 aand upper connection shaft 744 a 2. Thereby, the upper connection shaft744 a 2 may rotate relative to the first gearbox housing 741 a. A secondbearing 747 b may be inserted and installed between the inner surface ofthe first carrier 744 a and the washing shaft 732 a. Thereby, the firstcarrier 744 a and the washing shaft 732 a may rotate independently. Aplurality of second bearings 747 b may be provided. The second bearings747 b are spaced from each other in the vertical direction. A thirdbearing 747 c may be installed between the inner circumferential surfaceof the first gearbox housing 741 a and the outer side surface of thefirst carrier 744 a. Thereby, the first carrier 744 a may rotaterelative to the first gearbox housing 741 a. A fourth bearing 747 d maybe installed between the second carrier 744 b and the washing shaft 732a. Thereby, the washing shaft 732 a may rotate relative to the secondcarrier 744 b. A fifth bearing 747 e may be installed between the secondgearbox housing 741 b and the second carrier 744 b. Thereby, the secondgearbox housing 741 b may rotate relative to the second carrier 744 b. Asixth bearing 747 f may be installed between the first gearbox housing741 a and the second gearbox housing 741 b. Thereby, the second gearboxhousing 741 b may rotate relative to the first gearbox housing 741 a.

Referring to FIG. 21, the eighth embodiment, which will be describedbelow, has the following differences from the seventh embodiment: i) thedirection of rotation of the pulsator 122 is opposite to the directionof rotation of the drive motor 130, and the direction of rotation of thepulsator 122 is the same as the direction of rotation of the blade 123;ii) the pulsator 122 integrally rotates with the first ring gear 845 a,and the blade 123 integrally rotates with the second ring gear 845 b;iii) the first ring gear 845 a and the second ring gear 845 b are fixedby each other, and the second ring gear 845 b is fixed to the inner tubassembly 120. That is, the first ring gear 845 a and the second ringgear 845 b do not revolve; iv) the first carrier 841 a need not includeeither an upper connection shaft or a power transmission cap, and thefirst gearbox housing 841 a forms an upper connection shaft 841 a 2 anda power transmission cap 841 a 3.

Hereinafter, a power transmission unit 840 according to the eighthembodiment will be described in detail.

In the eighth embodiment, the direction of rotation of the pulsator 122is the same as the direction of rotation of the blade 123. The directionof rotation of the washing shaft 832 a, the direction of rotation of thefirst sun gear 842 a, and the direction of rotation of the second sungear 842 b are the same. The direction of rotation of the first ringgear 845 a, the direction of rotation of the second ring gear 845 b, thedirection of rotation of the pulsator 122, and the direction of rotationof the blade 123 are the same. The direction of rotation of the washingshaft 832 a, the first sun gear 842 a and the second sun gear 842 b isopposite to the direction of rotation of the first ring gear 845 a, thesecond ring gear 845 b, the pulsator 122 and the blade 123.

A ring gear accommodation groove is provided to the interior of thefirst gearbox housing 841 a. The first ring gear 845 a is inserted intoand fixed to the ring gear accommodation groove of the first gearboxhousing 841 a.

A ring gear accommodation groove is provided to the interior of thesecond gearbox housing 841 b. The second ring gear 845 b is insertedinto and fixed to the ring gear accommodation groove of the secondgearbox housing 841 b.

The first carrier 844 a and the second carrier 844 b are fixed by eachother. The second carrier 844 b is fixed to the inner tub assembly 120.The lower portion of the second carrier 844 b is fixed to the hub 124.The first carrier 844 a is fixed to the inner tub assembly 120 by thesecond carrier 844 b. That is, the first carrier 844 a, the secondcarrier 844 b and the inner tub assembly 120 do not make a rotationrelative to each other.

The first ring gear 845 a is fixed to the first gearbox housing 841 a. Aplurality of lugs is formed on one of the first gearbox housing 841 aand the first ring gear 845 a, and a plurality of lug accommodationgrooves to be engaged with the lugs is formed on the other one of thefirst gearbox housing 841 a and the first ring gear 845 a. The lugaccommodation grooves may be formed in the outer circumferential surfaceof the first ring gear 845 a, and spaced a certain distance from eachother in a circumferential direction. The lugs may be formed on theinner circumferential surface of the first gearbox housing 841 a at apredetermined distance from each other in the circumferential direction.The lugs are inserted into and coupled with the lug accommodationgrooves. Alternatively, the lugs may be formed on the outercircumferential surface of the first ring gear 845 a, and the lugaccommodation grooves may be formed in the inner side surface of thefirst gearbox housing 841 a. The lugs and the lug accommodation groovesprevent the first ring gear 845 a from rotating relative to the firstgearbox housing 841 a. The rotation power of the first ring gear 845 ais transmitted to the first gearbox housing 841 a.

The first gearbox housing 841 a and the first ring gear 845 a. The firstgearbox housing 841 a and the first ring gear 845 a rotate relative tothe inner tub assembly 120. As the first carrier 844 a is fixed to theinner tub assembly 120, the first ring gear 845 a rotates around aplurality of first planetary gears 843 a while being engaged with thefirst planetary gears 843 a. The first ring gear 845 a rotates about thefirst sun gear 842 a. The direction of rotation of the first ring gear845 a is opposite to the direction of rotation of the first sun gear 842a, and is identical to the direction of rotation of the first planetarygear 843 a. Revolutions per minute of the first ring gear 845 a aredetermined by the gear ratio between the first ring gear 845 a and firstsun gear 842 a and revolutions per minute of the first sun gear 842 a.

The first gearbox housing 841 a forms the upper connection shaft 841 a2. The upper connection shaft 841 a 2 integrally rotates with the firstgearbox housing 841 a. The upper connection shaft 841 a 2 is insertedinto and coupled with the shaft support groove 122 b 2 formed at thecenter of the bottom surface of the pulsator 122. The upper connectionshaft 841 a 2 transmits power to the pulsator 122.

The gearbox housing 841 a includes a power transmission cap 841 a 3disposed between the upper connection shaft 841 a 2 and the shaftsupport groove 122 b 2. The power transmission cap 841 a 3 is insertedand coupled between the upper connection shaft 841 a 2 and the shaftsupport groove 122 b 2. The interior of the power transmission cap 841 a3 is provided with a coupling portion allowing the upper connectionshaft 144 b to be press-fitted thereinto. Serration lugs fortransmitting rotational power are formed on the outer circumferentialsurface of the power transmission cap 841 a 3.

The second gearbox housing 841 b is not fixed to the inner tub assembly120. The second gearbox housing 841 b rotates relative to the inner tubassembly 120. The second gearbox housing 841 b is separated from thefirst gearbox housing 841 a. The first gearbox housing 841 a and thesecond gearbox housing 841 b are separately rotatable.

The second carrier 844 b is fixed to the inner tub assembly 120. Thesecond carrier 844 b is fixed to the hub 124. The second carrier 844 bis coupled to the center portion of the hub 124. A plurality of lugs anda plurality of lug accommodation grooves are formed between the secondcarrier 844 b and hub 124. Thereby, the second carrier 844 b is fixed bythe hub 124.

The second ring gear 845 b is fixed to the second gearbox housing 841 b.In order to transmit rotational power of the second ring gear 845 b tothe second gearbox housing 841 b, a plurality of lugs is formed on oneof the second gearbox housing 841 b and the second ring gear 845 b, anda plurality of lug accommodation grooves to be engaged with the lugs isformed on the other one of the second gearbox housing 841 b and thesecond ring gear 845 b. The lug accommodation grooves are formed on theouter circumferential surface of the second ring gear 845 b, and spaceda certain distance from each other in a circumferential direction. Thelugs are formed on the inner circumferential surface of the secondgearbox housing 841 b at a predetermined distance from each other in thecircumferential direction. The lugs are inserted into and coupled withthe lug accommodation grooves. Alternatively, the lugs may be formed onthe outer circumferential surface of the second ring gear 845 b, and thelug accommodation grooves may be formed on the inner side surface of thesecond gearbox housing 841 b.

The second gearbox housing 841 b and the second ring gear 845 b rotate.The second gearbox housing 841 b and the second ring gear 845 b rotaterelative to the inner tub assembly 120. A jig 146 for fixing the secondring gear 845 b need not be provided between pulsator 122 and blade 123.As the second carrier 844 b is fixed to the inner tub assembly 120, thesecond ring gear 845 b rotates around the second planetary gear 843 bwhile being engaged with the second planetary gear 843 b. The secondring gear 845 b rotates about the second sun gear 342 b. The directionof rotation of the second ring gear 845 b is opposite to the directionof rotation of the second sun gear 342 b, and is identical to thedirection of rotation of the second planetary gear 843 b. Revolutionsper minute of the second ring gear 845 b are determined by the gearratio between the second ring gear 845 b and second sun gear 342 b andrevolutions per minute of the second sun gear 342 b.

The blade 123 is rotated by the rotational power transmitted from thesecond gearbox housing 841 b. The second gearbox housing 841 b iscoupled with the center portion of the blade 123. The blade 123integrally rotates with the second gearbox housing 841 b. The blade 123integrally rotates with the second ring gear 845 b. A plurality of lugsand a plurality of lug accommodation grooves may be provided to theboundary surfaces between the second gearbox housing 841 b and blade123. The plurality of lugs is disposed to face the plurality of lugaccommodation grooves. The rotational power received by the secondgearbox housing 841 b is transmitted to the blade 123. The lugs or lugaccommodation grooves may be formed on the second gearbox housing 841 b,and the lug accommodation grooves or the lugs may be formed on the blade123. The direction of rotation of the blade 123 is opposite to thedirection of rotation of the drive motor 130.

The pulsator 122 receives rotational power through the upper connectionshaft 841 a 2 of the first gearbox housing 841 a. The upper connectionshaft 841 a 2 is vertically disposed at an upper portion of the washingshaft 832 a. The upper connection shaft 841 a 2 and the washing shaft832 a rotate independently. The direction of rotation of the pulsator122 is opposite to the direction of rotation of the drive motor 130.

The power transmission unit 840 includes a plurality of bearings 847 b,847 c, 847 d, 847 e, 847 f, which enable the washing shaft 832 a, upperconnection shaft 841 a 2, first and second carriers 844 a, 844 b, firstgearbox housing 841 a and second gearbox housing 841 b to rotaterelative to each other. A second bearing 847 b may be inserted andinstalled between the inner surface of the first carrier 844 a and thewashing shaft 832 a. Thereby, the first carrier 844 a and the washingshaft 832 a may rotate independently. A plurality of second bearings 848b may be provided. The second bearings 848 b are spaced from each otherin the vertical direction. A third bearing 847 c may be installedbetween the inner circumferential surface of the first gearbox housing841 a and the outer side surface of the first carrier 844 a or thesecond carrier 844 b. Thereby, the first and second carriers 844 a, 844b may rotate relative to the first gearbox housing 841 a. A fourthbearing 847 d may be installed between the second carrier 844 b and thewashing shaft 832 a. Thereby, the washing shaft 832 a may rotaterelative to the second carrier 844 b. A fifth bearing 847 e may beinstalled between the second gearbox housing 841 b and the secondcarrier 844 b. Thereby, the second gearbox housing 841 b may rotaterelative to the second carrier 844 b. A sixth bearing 847 f may beinstalled between the first gearbox housing 841 a and the second gearboxhousing 841 b. Thereby, the second gearbox housing 841 b may rotaterelative to the first gearbox housing 841 a.

Referring to FIG. 22, the ninth embodiment, which will be describedbelow, has the following differences from the seventh embodiment: i) thedirection of rotation of the blade 123 is the same as the direction ofrotation of the drive motor 130, and the direction of rotation of thepulsator 122 is the same as the direction of rotation of the blade 123;ii) the pulsator 122 integrally rotates with the first carrier 944 a,and the blade 123 integrally rotates with the second carrier 944 b; iii)the first carrier 944 a and the second carrier 944 b are fixed by eachother, and the first ring gear 945 a and the second ring gear 944 b arefixed to the inner tub assembly 120; iv) the power transmission unit 940includes a cheek 146 for fixing the first gearbox housing 941 a and thesecond gearbox housing 941 b.

Hereinafter, a power transmission unit 940 according to the ninthembodiment will be described in detail.

In the ninth embodiment, the direction of rotation of the pulsator 122is the same as the direction of rotation of the blade 123. The directionof rotation of the washing shaft 932 a, the direction of rotation of thefirst sun gear 942 a, and the direction of rotation of the second sungear 942 b, the direction of rotation of the second sun gear 942 b, thedirection of revolution of the first planetary gear 943 a and thedirection of revolution of the second planetary gear 943 b, thedirection of rotation of the peseta 122, and the direction of rotationof the blade 123 are the same.

A ring gear accommodation groove is provided to the interior of thefirst gearbox housing 941 a. The first ring gear 945 a is inserted intoand fixed to the ring gear accommodation groove of the first gearboxhousing 941 a.

A ring gear accommodation groove is provided to the interior of thesecond gearbox housing 941 b. The second ring gear 945 b is insertedinto and fixed to the ring gear accommodation groove of the secondgearbox housing 941 b.

The first ring gear 945 a and the second ring gear 945 b are fixed byeach other. The first ring gear 945 a and the second ring gear 945 b arefixed to the inner tub assembly 120. The first ring gear 945 a is fixedto the first gearbox housing 941 a, the second ring gear 945 b is fixedto the second gearbox housing 941 b, and the first gearbox housing 941 aand the second gearbox housing 941 b are fixed by each other. The firstgearbox housing 941 a and the second gearbox housing 941 b are fixed tothe inner tub assembly 120 by the jig 146. The first ring gear 945 a,the second ring gear 945 b and the inner tub assembly 120 two not make arotation relative to each other.

The first gearbox housing 941 a and the second gearbox housing 941 b arefixed by the jig 146. The jig 146 is disposed to connect the outercircumferential portion of the first gearbox housing 941 a or the secondgearbox housing 941 b with the base 121. The jig 146 includes a centerportion having a ring shape. The jig 146 includes a plurality ofextensions radially extending from the center portion toward the base. Acoupling portion is formed on the outer circumferential portion of thefirst gearbox housing 941 a or second gearbox housing 941 b. Thecoupling portion of the first gearbox housing 941 a or second gearboxhousing 941 b is coupled to the center portion of the jig 146. Thecenter portion of the jig 146 and the outer circumferential portion ofthe first gearbox housing 941 a or second gearbox housing 941 b arefastened to each other by a fastening member. The extensions of the jig146 may be fastened to the base 121 by a fastening member such as abolt.

The first ring gear 945 a is fixed to the first gearbox housing 941 a. Aplurality of lugs is formed on one of the first gearbox housing 941 aand the first ring gear 945 a, and a plurality of lug accommodationgrooves to be engaged with the lugs is formed on the other one of thefirst gearbox housing 941 a and the first ring gear 945 a. The lugaccommodation grooves may be formed in the outer circumferential surfaceof the first ring gear 945 a, and spaced a certain distance from eachother in a circumferential direction. The lugs may be formed on theinner circumferential surface of the first gearbox housing 941 a at apredetermined distance from each other in the circumferential direction.The lugs are inserted into and coupled with the lug accommodationgrooves. Alternatively, the lugs may be formed on the outercircumferential surface of the first ring gear 945 a, and the lugaccommodation grooves may be formed in the inner side surface of thefirst gearbox housing 941 a. The lugs and the lug accommodation groovesprevent the first ring gear 945 a from rotating relative to the firstgearbox housing 941 a. The first ring gear 945 a is fixed to the innertub assembly 120 by the first gearbox housing 941 a. In order to fix thefirst ring gear 945 a to the inner tub assembly 120, the first gearboxhousing 941 a is connected and fixed to the jig 146.

The second ring gear 945 b is fixed to the second gearbox housing 941 b.a plurality of lugs is formed on one of the second gearbox housing 941 band the second ring gear 945 b, and a plurality of lug accommodationgrooves to be engaged with the lugs is formed on the other one of thesecond gearbox housing 941 b and the second ring gear 945 b. The lugaccommodation grooves may be formed on the outer circumferential surfaceof the second ring gear 945 b, and spaced a certain distance from eachother in a circumferential direction. The lugs are formed on the innercircumferential surface of the second gearbox housing 941 b at apredetermined distance from each other in the circumferential direction.The lugs are inserted into and coupled with the lug accommodationgrooves. Alternatively, the lugs may be formed on the outercircumferential surface of the second ring gear 945 b, and the lugaccommodation grooves may be formed on the inner side surface of thesecond gearbox housing 941 b. The lugs and the lug accommodation groovesprevent the second ring gear 945 b from rotating relative to the secondgearbox housing 941 b. The second ring gear 945 b is fixed to the innertub assembly 120 by the second gearbox housing 941 b. In order to fixthe second ring gear 945 b to the inner tub assembly 120, the secondgearbox housing 941 b is connected and fixed to the jig 146.

As the first ring gear 945 a is fixed to the inner tub assembly 120, thefirst planetary gear 943 a revolves along the inner circumferentialsurface of the first ring gear 945 a, while being engaged with the firstring gear 945 a. The first planetary gear 943 a revolves around thefirst sun gear 942 a. The direction of revolution of the first planetarygear 943 a is identical to the direction of rotation of the first sungear 942 a. Revolutions per minute according to revolution of theplurality of first planetary gear 943 a may be set according to the gearratio between the first ring gear 945 a and the first sun gear 942 a.Revolutions per minute of the first carrier 944 a are equal torevelations per minute according to revolution of the plurality of firstplanetary gear 943 a. Revolutions per minute of the first carrier 944 aare determined by the gear ratio between the first ring gear 945 a andthe first sun gear 942 a and revolutions per minute of the first sungear 942 a.

As the second ring gear 945 b is fixed to the inner tub assembly 120,the second planetary gear 943 b revolves along the inner circumferentialsurface of the second ring gear 945 b, while being engaged with thesecond ring gear 945 b. The second planetary gear 943 b revolves aroundthe second sun gear 942 b. The direction of revolution of the secondplanetary gear 943 b is identical to the direction of rotation of thesecond sun gear 942 b. Revolutions per minute according to revolution ofthe plurality of second planetary gear 943 b may be set according to thegear ratio between the second ring gear 945 b and the second sun gear942 b. Revolutions per minute of the second carrier 944 b are equal torevelations per minute according to revolution of the plurality ofsecond planetary gear 943 b. Revolutions per minute of the secondcarrier 944 b are determined by the gear ratio between the second ringgear 945 b and the second sun gear 942 b and revolutions per minute ofthe second sun gear 942 b.

The first carrier 844 a is not fixed to the inner tub assembly 120. Thesecond carrier 844 b is not fixed to the inner tub assembly 120. Thefirst carrier 844 a rotates relative to the inner tub assembly 120. Thesecond carrier 844 b is not fixed to the inner tub assembly 120. Thesecond carrier 844 b rotates relative to the inner tub assembly 120. Thefirst carrier 844 a is separated from the second carrier 844 b. Thefirst carrier 844 a and the second carrier 844 b are separatelyrotatable.

The first carrier 944 a forms the upper connection shaft 944 a 2. Theupper connection shaft 944 a 2 integrally rotates with the first carrier944 a. The upper connection shaft 944 a 2 is inserted into and coupledwith the shaft support groove 122 b 2 formed at the center of the bottomsurface of the pulsator 122. The upper connection shaft 944 a 2transmits power to the pulsator 122.

The first carrier 944 a includes a power transmission cap 944 c disposedbetween the upper connection shaft 944 a 2 and the shaft support groove122 b 2. The power transmission cap 944 c is inserted and coupledbetween the upper connection shaft 944 a 2 and the shaft support groove122 b 2. The interior of the power transmission cap 944 c is providedwith a coupling portion allowing the upper connection shaft 144 b to bepress-fitted thereinto. Serration lugs for transmitting rotational powerare formed on the outer circumferential surface of the powertransmission cap 944 c.

The blade 123 is rotated by the rotational power transmitted from thesecond carrier 944 b. The rotational speed of the blade 123 is decreasedaccording to the gear ratio between the second sun gear 942 b and thesecond ring gear 945 b. The second carrier 944 b is fixed the blade 123.The second carrier 944 b is coupled to the center portion. The blade 123integrally rotates with the second carrier 944 b. A plurality of lugsand a plurality of lug accommodation grooves may be provided to theboundary surfaces between the second carrier 944 b and the blade 123.The plurality of lugs is disposed to face the plurality of lugaccommodation grooves. The rotational power of the second carrier 944 bis transmitted to the blade 123. The lugs or the lug accommodationgrooves may be formed on the second carrier 944 b, and the lugaccommodation grooves or the lugs may be formed on the blade 123.

The pulsator 122 receives rotational power through the upper connectionshaft 944 a 2 of the first carrier 944 a. The upper connection shaft 944a 2 is vertically disposed at an upper portion of the washing shaft 932a. The upper connection shaft 944 a 2 and the washing shaft 932 a rotateindependently. The direction of rotation of the pulsator 122 isidentical to the direction of rotation of the drive motor 130.

The power transmission unit 940 includes a plurality of bearings 947 a,947 b, 947 c, 947 d, 947 e, 947 f, which enable the washing shaft 932 a,the upper connection shaft 944 a 2, the second carrier 944 b and thefirst and second gearbox housings 941 a, 941 b to rotate relative toeach other. The power transmission unit 940 includes a plurality ofbearings 949 a, 949 b, 949 c, 949 d, 949 e, 949 f, which enable thewashing shaft 932 a, upper connection shaft 944 a 2, first carrier 944 aand first gearbox housing 941 a to rotate relative to each other. Afirst bearing 949 a may be inserted and installed between the firstgearbox housing 941 a and upper connection shaft 944 a 2. Thereby, theupper connection shaft 944 a 2 may rotate relative to the first gearboxhousing 941 a. A second bearing 949 b may be inserted and installedbetween the inner surface of the first carrier 944 a and the washingshaft 932 a. Thereby, the first carrier 944 a and the washing shaft 932a may rotate independently. A plurality of second bearings 949 b may beprovided. The second bearings 949 b are spaced from each other in thevertical direction. A third bearing 949 c may be installed between theinner circumferential surface of the first gearbox housing 941 a and theouter side surface of the first carrier 944 a. Thereby, the firstcarrier 944 a may rotate relative to the first gearbox housing 941 a. Afourth bearing 949 d may be installed between the second carrier 944 band the washing shaft 932 a. Thereby, the washing shaft 932 a may rotaterelative to the second carrier 944 b. A fifth bearing 949 e may beinstalled between the second gearbox housing 941 b and the blade 123.Thereby, the blade 123 may rotate relative to the second gearbox housing941 b. A sixth bearing 949 f may be installed between the innercircumferential surface of the second gearbox housing 941 b and theouter surface of the second carrier 944 b. Thereby, the second carrier944 b may rotate relative to the second gearbox housing 941 b.

Referring to FIG. 23, the tenth embodiment, which will be describedbelow, has the following differences from the seventh embodiment: i) thedirection of rotation of the pulsator 122 is opposite to the directionof rotation of the drive motor 130, and the direction of rotation of thepulsator 122 is the same as the direction of rotation of the blade 123;ii) the pulsator 122 integrally rotates with the first ring gear 1045 a,and the blade 123 integrally rotates with the second carrier 1045 b;iii) the first carrier 1044 a and the second ring gear 1045 b are fixedby each other, and the second ring gear 1045 b is fixed to the inner tubassembly 120; iv) the first carrier 1044 a need not include either anupper connection shaft or a power transmission cap, the first gearboxhousing 1041 a forms an upper connection shaft 1041 a 2 and a powertransmission cap 1041 a 3; v) the power transmission unit 1040 includesa jig 146 for fixing the second gearbox housing 1041 b and the firstcarrier 1044 a.

Hereinafter, a power transmission unit 1040 according to the tenthembodiment will be described in detail.

In the tenth embodiment, the direction of rotation of the pulsator 122is opposite to the direction of rotation of the blade 123. The powertransmission unit 1040 transmits power such that the direction ofrotation of the pulsator 122 is opposite to the direction of rotation ofthe blade 1210. The direction of rotation of the washing shaft 1032 a,the direction of rotation of the first sun gear 1042 a, the direction ofrotation of the second sun gear 1042 b, the direction of rotation of thesecond planetary gear 1043 b and the direction of rotation of the blade123 are the same. The direction of rotation of the pulsator 122 and thedirection of rotation of the first ring gear 1045 a are the same. Thedirection of rotation of the pulsator 122 is opposite to the directionof rotation of the drive motor 130. The direction of rotation of theblade 123 is the same as the direction of rotation of the drive motor130. The resulting effect is the same as the effect of the thirdembodiment.

A ring gear accommodation groove is provided to the interior of thefirst gearbox housing 1041 a. The first ring gear 1045 a is insertedinto and fixed to the ring gear accommodation groove of the firstgearbox housing 1041 a.

A ring gear accommodation groove is provided to the interior of thesecond gearbox housing 1041 b. The second ring gear 1045 b is insertedinto and fixed to the ring gear accommodation groove of the secondgearbox housing 1041 b.

The first carrier 1044 a and the second carrier 1044 b are fixed by eachother. The second ring gear 1045 b is fixed to the inner tub assembly120. The second ring gear 1045 b is fixed to the second gearbox housing1041 b, and the second gearbox housing 1041 b is fixed to the inner tubassembly 120 by the jig 146. The first carrier 1044 a, the second ringgear 1045 b and the inner tub assembly 120 do not make a rotationrelative to each other.

The jig 146 is disposed to connect the outer circumferential portion ofthe second gearbox housing 1041 b to the base 121. The jig 146 includesa center portion having a ring shape. The jig 146 includes a pluralityof extensions radially extending from the center portion toward thebase. A coupling portion is formed on the outer circumferential portionof the second gearbox housing 1041 b. The coupling portion of the secondgearbox housing 1041 b is coupled to the center portion of the jig 146.The center portion of the jig 146 and the outer circumferential portionof the second gearbox housing 1041 b are fastened to each other by afastening member. The extensions of the jig 146 may be fastened to thebase 121 by a fastening member such as a bolt.

The first ring gear 1045 a is fixed to the first gearbox housing 1041 a.A plurality of lugs is formed on one of the first gearbox housing 1041 aand the first ring gear 1045 a, and a plurality of ring gearaccommodation grooves to be engaged with the lugs is formed on the otherone of the first gearbox housing 1041 a and the first ring gear 1045 a.The ring gear accommodation grooves may be formed in the outercircumferential surface of the first ring gear 1045 a, and spaced acertain distance from each other in a circumferential direction. Thelugs may be formed on the inner circumferential surface of the firstgearbox housing 1041 a at a predetermined distance from each other inthe circumferential direction. The lugs are inserted into and coupledwith the ring gear accommodation grooves. Alternatively, the lugs may beformed on the outer circumferential surface of the first ring gear 1045a, and the ring gear accommodation grooves may be formed on the innerside surface of the first gearbox housing 1041 a. The lugs and the lugaccommodation grooves prevent the first ring gear 1045 a from rotatingrelative to the first gearbox housing 1041 a. The rotational power ofthe first ring gear 1045 a is transmitted to the first gearbox housing1041 a.

The first gearbox housing 1041 a and the first ring gear 1045 a rotate.The first gearbox housing 1041 a and the first ring gear 1045 a rotaterelative to the inner tub assembly 120. As the first carrier 1044 a isfixed to the inner tub assembly 120, the first ring gear 1045 a rotatesaround the first planetary gear 1043 b while being engaged with thefirst planetary gear 1043 a. The first ring gear 1045 a rotates aboutthe first sun gear 342 b. The direction of rotation of the first ringgear 1045 a is opposite to the direction of rotation of the first sungear 1042 a, and is identical to the direction of rotation of the firstplanetary gear 1043 a. Revolutions per minute of the first ring gear1045 a are determined by the gear ratio between the first ring gear 1045a and first sun gear 1042 a and revolutions per minute of the first sungear 1042 a.

The first gearbox housing 1041 a forms the upper connection shaft 1041 a2. The upper connection shaft 1041 a 2 integrally rotates with the firstgearbox housing 1041 a. The upper connection shaft 1041 a 2 is insertedinto and coupled with the shaft support groove 122 b 2 formed at thecenter of the bottom surface of the pulsator 122. The upper connectionshaft 1041 a 2 transmits power to the pulsator 122.

The gearbox housing 1041 a includes a power transmission cap 1041 a 3disposed between the upper connection shaft 1041 a 2 and the shaftsupport groove 122 b 2. The power transmission cap 1041 a 3 is insertedand coupled between the upper connection shaft 1041 a 2 and the shaftsupport groove 122 b 2. The interior of the power transmission cap 1041a 3 is provided with a coupling portion allowing the upper connectionshaft 144 b to be press-fitted thereinto. Serration lugs fortransmitting rotational power are formed on the outer circumferentialsurface of the power transmission cap 1041 a 3.

The second ring gear 1045 b is fixed to the second gearbox housing 1041b. A plurality of lugs is formed on one of the second gearbox housing1041 b and the second ring gear 1045 b, and a plurality of ring gearaccommodation grooves to be engaged with the lugs is formed on the otherone of the second gearbox housing 1041 b and the second ring gear 1045b. The ring gear accommodation grooves may be formed in the outercircumferential surface of the second ring gear 1045 b, and spaced acertain distance from each other in a circumferential direction. Thelugs may be formed on the inner circumferential surface of the secondgearbox housing 1041 b at a predetermined distance from each other inthe circumferential direction. The lugs are inserted into and coupledwith the ring gear accommodation grooves. Alternatively, the lugs may beformed on the outer circumferential surface of the second ring gear 1045b, and the ring gear accommodation grooves may be formed on the innerside surface of the second gearbox housing 1041 b. The lugs and the lugaccommodation grooves prevent the second ring gear 1045 b from rotatingrelative to the second gearbox housing 1041 b. The second ring gear 1045b is fixed to the inner tub assembly 120 by the second gearbox housing1041 b. To fix the second ring gear 1045 b to the inner tub assembly120, the second gearbox housing 1041 b is connected and fixed to the jig146.

The first ring gear 1045 a is not fixed to the inner tub assembly 120.The first ring gear 1045 a rotates relative to the inner tub assembly120.

The second carrier 1044 b is not fixed to the inner tub assembly 120.The second carrier 1044 b rotates relative to the inner tub assembly120.

The blade 123 is rotated by the rotational power transmitted from thesecond carrier 1044 b. The rotational speed of the blade 123 isdecreased according to the gear ratio between the second sun gear 1042 band the second ring gear 1045 b. The power transmission unit 940 mayfurther include a blade support member 1049 b connected between theblade 123 and the second carrier 1044 b. The second carrier 1044 b mayfix the blade support member 1049 b, and the blade support member 1049 bmay be coupled with the center portion of the blade 123. The blade 123integrally rotates with the second carrier 1044 b. A plurality of lugsand a plurality of lug accommodation grooves may be provided to theboundary surfaces between the blade support member 1049 b and the blade123. The plurality of lugs is disposed to face the plurality of lugaccommodation grooves. The rotational power of the blade support member1049 b is transmitted to the blade 123. The lugs or the lugaccommodation grooves may be formed on the blade support member 1049 b,and the lug accommodation grooves or the lugs may be formed on the blade123. The blade support member 1049 b may be integrated with the secondcarrier 1044 b.

The pulsator 122 receives rotational power through the upper connectionshaft 1041 a 2 of the first gearbox housing 1041 a. The upper connectionshaft 1041 a 2 is vertically disposed at an upper portion of the washingshaft 1032 a. The upper connection shaft 1041 a 2 and the washing shaft1032 a rotate independently. The direction of rotation of the pulsator122 is opposite to the direction of rotation of the drive motor 130.

The power transmission unit 1040 includes a plurality of bearings 1047a, 1047 b, 1047 c, 1047 d, 1047 e, 1047 f, which enable the washingshaft 1032 a, first and second carriers 1044 a, 1044 b, first gearboxhousing 1041 a and second gearbox housing 1041 b to rotate relative toeach other. A first bearing 1047 a may be inserted and installed betweenthe inner circumferential surface of the first gearbox housing 1041 aand the outer side surface of the first carrier 1044 a. Thereby, thefirst carrier 1044 a may rotate relative to the first gearbox housing1041 a. A second bearing 1047 b may be inserted and installed betweenthe inner surface of the first carrier 1044 a and the washing shaft 1032a. Thereby, the first carrier 1044 a and the washing shaft 1032 a mayrotate independently. A plurality of second bearings 10410 b may beprovided. The second bearings 10410 b are spaced from each other in thevertical direction. A third bearing 1047 c may be installed between theouter side surface of the second carrier 1044 b and the inner sidesurface of the second gearbox housing 1041 b. Thereby, the secondcarrier 1044 b may rotate relative to the second gearbox housing 1041 b.A fourth bearing 1047 d may be installed between the second carrier 1044b and the washing shaft 1032 a. Thereby, the washing shaft 1032 a mayrotate relative to the second carrier 1044 b. A fifth bearing 1047 e maybe installed between the blade support member 1049 b and the secondgearbox housing 1041 b. Thereby, the blade support member 1049 b mayrotate relative to the second gearbox housing 1041 b.

As is apparent from the above description, according to embodiments ofthe present invention, water may be sprayed upward at a strong pressure,detergent dissolution and fabric soaking may be quickly implemented, andthe degree of detergent dissolution may be remarkably increased.

In addition, detergent dissolution and fabric soaking may be easilyimplemented even with a small amount of water. Thereby, water usage maybe reduced.

As one drive motor is used to rotate a blade at a relatively high numberof revolutions per minute and to rotate a pulsator at a relatively lownumber of revolutions per minute, the pumping pressure and pumping headmay be increased, smooth washing may be performed, and the degree ofwear of the laundry and rotation load may be lowered.

In addition, as a power transmission unit for transmitting drive powerfrom one drive motor is provided, the function of the present inventionmay be achieved through a single shaft, and the need for a separatedrive motor and change of the shaft may be eliminated. Further, thecontrol operation may be simple.

In addition, as a planetary gear module is used, torque load to a drivemotor may be reduced. In addition, energy may be saved as the motor isdriven in a high-efficiency region.

In addition, as the blade stirs wash water in the direction opposite tothe direction of rotation of the pulsator, the rotational speed of theblade relative to the rotational speed of the pulsator may be increased.Thereby, the degree of detergent dissolution and washing performance maybe enhanced.

In addition, as wash water is stirred by a blade in a direction oppositeto the direction of stirring by the pulsator, vibration generated in thepulsator may be reduced in the case when laundry washed which areintroduced and put on the pulsator are concentrated at one position byrotation of the pulsator.

Further, as the pumped wash is caused to pass through a filter unit,impurities such as lint may be easily removed.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that some or all of the embodiments described above may beselectively combined such that various modifications, additions andsubstitutions can be made, without departing from the scope and spiritof the invention as disclosed in the accompanying claims.

1. A washing machine comprising: an inner tub assembly for accommodating laundry; a pulsator rotatably provided to an inner lower portion of the inner tub assembly; a blade installed below of the pulsator to be rotatable independently from the pulsator, the blade being configured to pump wash water to raise the wash water to an upper end of the inner tub assembly; a drive motor providing rotational power to the pulsator and the blade; and a power transmission unit transmitting power of the drive motor to the pulsator and the blade, respectively, wherein the power transmission unit comprises: a first planetary gear module transmitting power to the pulsator such that a rotational speed of the pulsator is decreased, and a second planetary gear module transmitting power to the blade such that a rotational speed of the blade is decreased.
 2. The washing machine according to claim 1, wherein the first planetary gear module is disposed at an upper side of the second planetary gear module.
 3. The washing machine according to claim 1, further comprising: a washing shaft transmitting the rotational power of the drive motor, wherein the first planetary gear module comprises: a first sun gear connected to the washing shaft and integrally rotating with the washing shaft; a first planetary gear rotating by being engaged with an outer circumferential surface of the first sun gear; a first carrier connecting the first planetary gear using a first planetary gear connection shaft, the first planetary gear connection shaft being coupled with the first planetary gear by penetrating a center portion of the first planetary gear; and a first ring gear having an inner side engaged with the first planetary gear, wherein the second planetary gear module comprises: a second sun gear connected to the washing shaft and integrally rotating with the washing shaft; a second planetary gear rotating by being engaged with an outer circumferential surface of the second sun gear; a second carrier connecting the second planetary gear using a second planetary gear connection shaft, the second planetary gear connection shaft being coupled with the second planetary gear by penetrating a center portion of the second planetary gear; and a second ring gear having an inner side engaged with the second planetary gear.
 4. The washing machine according to claim 3, wherein the pulsator integrally rotates with one of the first carrier and the first ring gear, wherein the other one of the first carrier and the first ring gear is fixed to the inner tub assembly.
 5. The washing machine according to claim 3, wherein the pulsator integrally rotates with one of the first carrier and the first ring gear, wherein the other one of the first carrier and the first ring gear is fixed to one of the second carrier and the second ring gear.
 6. The washing machine according to claim 3, wherein the blade integrally rotates with one of the second carrier and the second ring gear, wherein the other one of the second carrier and the second ring gear is fixed to the inner tub assembly.
 7. The washing machine according to claim 3, wherein the blade integrally rotates with one of the second carrier and the second ring gear, wherein the other one of the second carrier and the second ring gear is fixed to one of the first carrier and the first ring gear.
 8. The washing machine according to claim 3, wherein the pulsator integrally rotates with one of the first carrier and the first ring gear, and the blade integrally rotates with one of the second carrier and the second ring gear, wherein the other one of the first carrier and the first ring gear is fixed to the other one of the second carrier and the second ring gear, and the other one of the second carrier and the second ring gear is fixed to the inner tub assembly.
 9. The washing machine according to claim 8, wherein the power transmission unit transmits power such that a direction of rotation of the pulsator is opposite to a direction of rotation of the blade.
 10. The washing machine according to claim 9, wherein the pulsator integrally rotates with the first carrier, and the blade integrally rotates with the second ring gear, wherein the first ring gear, the second carrier and the inner tub assembly are fixed by each other.
 11. The washing machine according to claim 9, wherein the pulsator integrally rotates with the first ring gear, and the blade integrally rotates with the second carrier, wherein the first carrier, the second ring gear and the inner tub assembly are fixed by each other.
 12. The washing machine according to claim 3, wherein the first planetary gear module comprises: a first gearbox housing accommodating the first sun gear, the first planetary gear, the first ring gear and the first carrier, wherein the second planetary gear module comprises: a second gearbox housing accommodating the second sun gear, the second planetary gear, the second ring gear and the second carrier, wherein the first gearbox housing and the second gearbox housing are rotatable relative to each other.
 13. The washing machine according to claim 3, wherein the first planetary gear module comprises: a first gearbox housing accommodating the first sun gear, the first planetary gear, the first ring gear and the first carrier, wherein the first ring gear is fixed to the first gearbox housing, wherein the first carrier forms an upper connection shaft penetrating an upper surface of the first gearbox housing, and the pulsator receives rotational power transmitted from the first carrier via the upper connection shaft.
 14. The washing machine according to claim 3, wherein the first planetary gear module comprises: a first gearbox housing accommodating the first sun gear, the first planetary gear, the first ring gear and the first carrier, wherein the first ring gear is fixed to the first gearbox housing, wherein the first gearbox housing forms an upper connection shaft, and the pulsator receives rotational power transmitted from the first gearbox housing via the upper connection shaft.
 15. The washing machine according to claim 3, wherein the second planetary gear module comprises: a second gearbox housing accommodating the second sun gear, the second planetary gear, the second ring gear and the second carrier, wherein the second ring gear is fixed to the second gearbox housing, wherein the blade is fixed to the second gearbox housing.
 16. The washing machine according to claim 15, wherein the second carrier is fixedly coupled with a lower surface of the inner tub assembly.
 17. The washing machine according to claim 3, wherein the second planetary gear module comprises: a second gearbox housing accommodating the second sun gear, the second planetary gear, the second ring gear and the second carrier, wherein the second ring gear is fixed to the second gearbox housing, wherein the blade is fixed to the second carrier at a lower side of the second gearbox housing.
 18. The washing machine according to claim 17, further comprising: a jig provided between the pulsator and the blade and extending from an outer circumferential portion of the power transmission unit in a radial direction of the inner tub assembly, the jig being fastened to an inner bottom surface of the inner tub assembly, wherein the second gearbox housing is fixed to the jig.
 19. The washing machine according to claim 1, wherein, when viewed from an upper side of the pulsator, the blade is disposed to be fully hidden.
 20. The washing machine according to claim 1, further comprising: a wash water circulation module for guiding the wash water moved by the blade to an upper side of the inner tub assembly to spray the wash water. 